NASKAR

2006-06-05T17:28:00.000-07:00

Java Notes:

1. The singly rooted hierarchy in Java
The advantage s are:
1. All objects in a singly rooted hierarchy have interfcase in common.
2. The singly rooted hierarchy makes it easier to implement garbage collector.
3. A singly rooted hierarchy, along with creating all objects on the heap, greatly simplifies argument passing..... don't kow how though

2. Where storage of object lives
It’s useful to visualize some aspects of how things are laid out while the program is running—in particular how memory is arranged. There are six different places to store data:

a. Registers. This is the fastest storage because it exists in a place different from that of other storage: inside the processor. However, the number of registers is severely limited, so registers are allocated by the compiler according to its needs. You don’t have direct control, nor do you see any evidence in your programs that registers even exist.

b. The stack. This lives in the general random-access memory (RAM) area, but has direct support from the processor via its stack pointer. The stack pointer is moved down to create new memory and moved up to release that memory. This is an extremely fast and efficient way to allocate storage, second only to registers. The Java compiler must know, while it is creating the program, the exact size and lifetime of all the data that is stored on the stack, because it must generate the code to move the stack pointer up and down. This constraint places limits on the flexibility of your programs, so while some Java storage exists on the stack—in particular, object references—Java objects themselves are not placed on the stack.

c. The heap. This is a general-purpose pool of memory (also in the RAM area) where all Java objects live. The nice thing about the heap is that, unlike the stack, the compiler doesn’t need to know how much storage it needs to allocate from the heap or how long that storage must stay on the heap. Thus, there’s a great deal of flexibility in using storage on the heap. Whenever you need to create an object, you simply write the code to create it by using new, and the storage is allocated on the heap when that code is executed. Of course there’s a price you pay for this flexibility. It takes more time to allocate heap storage than it does to allocate stack storage (if you even could create objects on the stack in Java, as you can in C++).

d. Static storage. “Static” is used here in the sense of “in a fixed location” (although it’s also in RAM). Static storage contains data that is available for the entire time a program is running. You can use the static keyword to specify that a particular element of an object is static, but Java objects themselves are never placed in static storage.

e. Constant storage. Constant values are often placed directly in the program code, which is safe since they can never change. Sometimes constants are cordoned off by themselves so that they can be optionally placed in read-only memory (ROM), in embedded systems.

f. Non-RAM storage. If data lives completely outside a program, it can exist while the program is not running, outside the control of the program. The two primary examples of this are streamed objects, in which objects are turned into streams of bytes, generally to be sent to another machine, and persistent objects, in which the objects are placed on disk so they will hold their state even when the program is terminated. The trick with these types of storage is turning the objects into something that can exist on the other medium, and yet can be resurrected into a regular RAM-based object when necessary. Java provides support for lightweight persistence, and future versions of Java might provide more complete solutions for persistence.

3. "==" operator in Java compares Object reference and if we really wants to compare the actual content of the object we should use "equals()".

4. A class containing abstract methods is called an abstract class. If a class contains one or more abstract methods, the class itself must be qualified as abstract.

5. Inheritance vs Composition

6. Difference between abstract and interface.
a. Declare an interface using the keyword interface.
b. An interface may extend zero or more interfaces if it likes, but it cannot extend a class, because then it would inherit functionality, and interfaces cannot have functionality. They can only talk about it.
c. Interface methods cannot be static.
d. Interface methods are implicitly abstract. For that reason, you cannot mark them final (duh), synchronized, or native because all of these modifiers tell how you're going to implement the method, and you're voluntarily giving up that ability when you write the method in an interface.
All interface methods are implicitly abstract and public, regardless of what you write in the interface definition! It is true. The interface method declaration void biteIt(int times), despite its apparent access level of default, actually has public access. Try it. If you write a class in another package beyond the visibility of default access, and include the seemingly legal implementation of
void biteIt(int times) { ; },
the compiler will tell you that you cannot reduce the visibility of the method from public to default. They're all abstract; they're all public.
An interface can define variables. But all variables defined in an interface must be declared public, static, and final. Many Java programmers have adopted the practice of defining only variables within an interface and putting constants in it. This works to get at shared constants, but it is a workaround and is no longer necessary if you're using J2SE SDK 5.0. It features a new static import facility that allows you to import constants just as you would a class or package.
It should be obvious by now that an interface cannot implement another interface or a class.
You may modify your methods using the keyword abstract if you like, but it will have no effect on compilation. Methods in an interface are already abstract, and the Java Language Specification says that its use in interfaces is obsolete.

Likewise, the interface itself is already abstract. So you can do this if you want: public abstract interface Chompable {}. But there's no point; it's redundant.
Interfaces have default access by default (!). So this is legal: interface Chompable { }. But if you want your interface to have public access, use that modifier in the interface declaration.
You cannot declare an interface as having private access. It doesn't make any sense. No one could implement it. So private interface Chompable { } gets you a compiler error for your trouble.
public, static, and final are implicit on all field declarations in an interface.
There are some weird things to keep in mind.
Interfaces can be declared private or protected if they are declared nested inside another class or interface. The following will compile, though its usefulness is dubious at best.
public class interface test
{
private interface myinterface{ }
}

Only an inner class of the class of which the interface is declared can implement the interface.

7: . Can an anonymous class be declared as implementing an interface and extending a class?
Answer: An anonymous class may implement an interface or extend a superclass, but may not be declared to do both.
8. What's the purpose of the Runtime class?
9. What's the purpose of the system class?
10. Difference between Hashtable and Hashmap?

11. Which class should you use to obtain design information about an object?
The Class class is used to obtain information about an object's design.

12. Difference between equals() and == operator in Java
The equals() method compares the characters that make up String objects. It performs this comparison by putting the characters of the String objects into two char arrays and comparing the two arrays. The method returns true if all the elements of the char arrays match and false otherwise.
The == operator compares two object references to see whether they refer to the same instance. A pool of strings, initially empty, is maintained privately by the class String. All literal strings and string-valued constant expressions are interned there. You can also add your own strings to this pool by calling the intern() method. If the pool already contains a string equal to your String object, as determined by the equals(Object) method, then the string from the pool is returned. Otherwise, your String object is added to the pool and a reference to it is returned. It follows that, for any two strings s and t, s.intern()==t.intern() is true if and only if s.equals(t) is true.
To sum up: The equals() method determines whether two strings have the same characters, whereas the == operator determines if two operands refer to the same String object. == actually tests to see if the references in the variables point to the same memory address.

13. Why is String immutable and final?
the contents of the String class cannot be changed. any method that you might expect to modify the contents actually returns a new instance.
if you don't like this behaviour you might think of sub-classing String to provide methods that do alter the contents. but this isn't possible because the class is "final".
to see why, i think you have to look at how java passes arguments. machine-level values - ints, floats and the like - are passed by value. if you call foo.bar(i) then modifying the passed integer within the bar method won't alter the value of i (of course!).
however, if we pass an object into a method, where the object's contents are changed, then the effect will be seen outside the call. this is passing by reference:
class Foo { void changeStack( Stack inside ) { inside.pop( ) ; } }
Stack s ; s.push( new Object( ) ) ; System.out.println( s.size( ) ) ; // here s has size 1 Foo f = new Foo( ) ; f.changeStack( s ) ; System.out.println( s.size( ) ) ; // here s has size 0
again, this is obvious, but note that it is different to the way in which the machine-level values behave.
so how does this apply to String? unlike ints, literal strings (sequences of characters in quotes) are not machine-level values - they are String objects. so, in theory, passing "a quoted string" to a method might result in the string changing value!
class FooFoo { void changeString( String inside ) { inside.append( " world" ) ; // pretend this changes the String... } }
String s = "hello" ; Foo f = new Foo( ) ; f.changeString( s ) ; System.out.println( s ) ; // ...then this would be "hello world"...
f.changeString( "strange" ) ; // ...and what happens here?!
to avoid strange things like this last value (where a quoted string would change value) the java designers would either have to have make "quoted strings" machine-level values or introduce the idea of const objects (similar to C++).
instead, the pragmatic solution is to make sure that the Sting class can't change its contents - hence it is immutable and final.
and because String is immutable and final, it behaves as though it is passed by value, not reference.
one final comment: classes like Integer and Float behave in the same way. this avoids confusion, but also suggests that the compiler could make int and Integer equivalent (in the same way a "quoted string" and String are equivalent). this would make the language cleaner - i don't understand why this doesn't happen (i understand the performance advantages, but couldn't the compiler hide these from view, making int a compiler optimisation for the Integer class)?
Question: What is the Set interface?Answer: The Set interface provides methods for accessing the elements of a finite mathematical set. Sets do not allow duplicate elements.

14. What is the List interface?
The List interface provides support for ordered collections of objects.

15. What is the difference between the File and RandomAccessFile classes?
The File class encapsulates the files and directories of the local file system. The RandomAccessFile class provides the methods needed to directly access data contained in any part of a file.

16. Collection classes in Java? Ordered and unordered and collection and duplicate items
17. util.concurrent package in java
18. Inheritance and constructor calling order
19. Exception handling in java
20. What is Class loader in Java
21. Reflection in Java

2006-05-15T00:15:00.000-07:00

PM interview questions:

General Product Management:

1. Why do you want to move to Product Management?
Answer #1: I wanted to see the products I develop succeed. As a software engineer, and later a lead developer, I was deeply involved with how the product worked, but I was spending more time implementing than understanding the how and why of certain features appearing in Python on the screen in front of me. I was working as lead engineer at a startup company named Personal Spider when we missed the mark with a few product releases. I decided to move upstream and gather better requirements before sitting down to code with my team in a "measure twice, cut once" type of mentality. It led to better product, and I was hooked.

1 a. What is the role a Product Manager.
Answer: Product Managers will not be closely supervised. Little to no authority will be handed to PM. PM will not have direct managerial oversight for the people who work on your stuff. PM will be highly accountable for success or failure. As a PM it's very important to remember: a) Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity. b) Communicate to different people in their own language and find out what motivates them.

1 b. How to get respect from engineers.
Answer: Clear obstacles, Always take the blame, Explain the why, Update engineers with the information about how the product is bringing money and business in the company.

1 c. How to get respect from sales?
Answer: Know their numbers, get on phone with customers, Make promises so don't have to.

1 d. How to get respect from executives?
Answer: Have a vision, Be patient, know your competition, make your commitments.

1 e. How do you estimate the work?
Answer: Rule of thumb for estimates:
- Likely estimate (L) "How long do you think it will take"
- Pessimistic estimate (P) "Ok, but what's the longest it could take, accounting for unforseen roadblocks?"
- Optimistic estimate (O) "What's the least amount of time required is everything goes well?"

[ O + (Lx4) + P ] / 6

2. What are the gretest skills of a Product Manager?

3. What are the draw backs of a Product Manager?

4. What are the Pros and Cons of eBay web site?

5. What metrics you will be using to monitor the features of the site.

6. Where do you want to see yourself in 2 years
Answer: Well ultimately that will depend on my performance on the job and on the growth opportunities offered to me. I have already demonstrated leadership characteristics in all of the jobs I've held, so I'm very confident that I will take on progressively greater responsibilities in the future. I enjoy being part of product and technology strategy and helping the company grow and simultaneously grow with the company. It's very rewarding.

7. What is the biggest advantage of having a technical background?
Answer: Having a technical background allows you to better determine what can realistically be accomplished by your team. You can dig deep into various ways of approaching a product or industry, emerge with some best practices, and sit down to build a product. A technical background creates better communication between managers and engineers while still letting each group apply their individual expertise.

8: What is the biggest disadvantage?
Answer: It's possible to geek out too much. The latest technologies, optimizations, and rewriting code bases from the ground up might sound great and exciting, but do they really help the bottom line? Will the average user notice the difference?

9. What was the biggest lesson you learned when you moved from engineering to product management?
Answer: I respected sales and marketing channels a lot more. I realized that building a great product is not enough, people need to learn why it's great and actually use the tool. Most releases won't be perfect right away, and I learned to adapt and change with the right inputs from my user base to create a better product.

# 10. What aspects of product management do you find the least interesting and why?
Answer: Politics and clamoring for resources is not too fun, but is present in most work environments. Ideally I would have infinite time and money with the best designers, engineers, sales, and business development people the world as to offer, but most often you're left cutting features and sacrificing ideals for reality.

#11. What is the difference between a BRD and a PRD?
Answer: The business requirement document is sometimes referred as the marketing requirement document (MRD). It discusses the requirements at a very high level from a business perspective. It describes the problem that need to be resolved, the market opportunity, and sometimes the competitor offerings. It justifies if a development project should be initiated. The business requirement document is not tie to any given development release and should avoid using the product specific terms. Sometimes the requirements are described in a such neutral way that you cannot tell which module or applications will be impacted. Actually, the business requirements are more like a RFP from some prospects. It is a user view of the solution.
The product requirement document is sometime referred as the product requirement specification or functional specification. It describes the expected functionality from a product. It is an outcome from the requirement analysis process. It interprets the business requirements by mapping and describing them using the product terminology. It is the document to communicate the business requirement to the product stakeholders. A product requirement document should be written with a product release in mind although not all features identified need to be scoped in. The key point is that the detail scoping decision can be made based on the product requirement document. It is the product requirement document identifies the scope of a development project. In the PMBOK, the product requirement document can be regarded as the scope statement for initiating a development project. It defines the features and is the product view of the solution.
At some stage, the product requirement should be baselined for functional design. It should be subject to the change control process for scope control. Scope creeping can thus be avoid. However, it worth mentioning that the requirement analysis is a iteration process. You should not be too rigid on changing the product requirement during design phase. You should not feel hesitate to contact customers to clarify the requirement.

#12. What are the steps and process when we want to design a new process.

eBay Product Management

#1 : What is the Global Product Planning process?
Answer: The Global Product Planning Process is the collection of steps required to move an initiative from concept through to scheduling on the roadmap. These steps or "phases" are: Concept> BRD> Scoping> NPV> Approval> Committed> Launched.
In the Concept phase, Product Management and the Business Units work together to vet the good ideas. The goal of this phase is to do the up-front work necessary to determine if a feature is a solid business idea with feasible implementation options. Once an idea is vetted and preliminarily approved, the Business Partner submits a Business Requirements Document (BRD) to the Product Manager. In the Scoping Phase, the Product Manager uses the BRD to craft a scope request. The scoping team then estimates the resources required to support the initiative. The Business Partner for the initiative then drives it though NPV process - a set of calculations (done in cooperation with the Finance Rep.) to determine the NPV and Fit score of the initiative in preparation for the presentation to the Product Evaluation Subcommittee. The Product Evaluation Subcommittee reviews all initiatives and gives them either an approved ("Green/Green") status or a not approved status. Any Product Evaluation Subcommittee-approved projects go into the queue for an overall ranking and scheduling. Any projects that are not approved are sent back through the process or eliminated. Once all the approved initiatives are ranked, Product Management and Design Labs resources are assigned, PRD dates are established, and Product Development resources are booked. The completed Product Roadmap, including LTS dates, is then presented to Product Council and to Executive Staff for approval

#2: My feature has been scoped. What are the next steps?
The PM is responsible for communicating the scope back to the BU. Assuming that the BU decides to move forward with this initiative as defined and scoped, they would take this through the NPV process. Often the BU decides that they would like to try a different approach and will resubmit this initiative, slightly modified, for rescope.
Occasionally, when a scoping estimate is returned, the BU decides to try a different approach to the project and will request PM to resubmit this initiative, slightly modified, for rescope. If a project team does not go with the first official scoping estimate for a feature, it is critical that the rescope data is captured to accurately reflect the scope that the team decides to use. For example, any requests for rescopes or notes from offline conversations with the original scoper must be officially submitted to the scoping alias. Or if a team decides to select a subset of the scoped features, the data must also be submitted to the scoping alias so that, when the time comes, the feature can be scheduled accordingly.

#3: What is the NPV process and how do I get my project through it?
The Net Present Value (NPV) process is driven by the Business Unit with the goal of identifying the costs and benefits of a given feature. The Business Partner is responsible for collecting the data that feeds into the NPV calculations and working with their Finance Rep to come up with both NPV for a given project as well as a Fit score.
Product Managers are expected to work with their Business Partners to help provide some of the data needed to run the NPV numbers. Once a project has been scoped, a Product Manager should make sure to communicate scope estimates to the sponsoring BU and to keep track of whether the BU plans to do NPV and what the status is.

#4: What is a Fit score?
A Fit score attempts to capture the more qualitative aspects of an initiative; fit from a Strategic, Community, Product Principle, User Experience, and Technical Complexity perspective

#5: How are projects booked?
Once features have been scoped, through the NPV process and approved, they are eligible for booking resources.
New Initiatives
We typically book PD resources based on the information provided in the scope document. We will get as detailed as we can (in terms of PD components, for example, XSL, Isapi, Search, Batch, etc.) based upon the information available to us in this document. The scope document is (by design) high level, so we may not have all the project details at this point in the process. (Based upon past projects, Project Managers may often have much more detail on what is required than Global Product Planning does when booking.)
In addition to PD scoping, we collect "high", "medium" & "low" impact estimates from DataWarehouse and Ops, and a Yes/No on whether JAD is required from Architecture. Once PD resources have been booked we circle back with these groups to ensure that they know when PD plans to deliver their components. As each group moves forward with planning their own upcoming roadmap they will have pertinent data such as PRD dates, development dates, and LTS dates for each initiative and will take this all into consideration while solidifying their own plans.
Once a project is approved, it's also booked by Deisgn Labs. DL works with Product Management and GPP to identify what the priority, possible dependancies and target dates are. The project is then allocated to resources on User Interface, Usability and Creative resource maps and a target PRD date is established.
Existing Projects For existing (meaning previously booked) projects requiring new or additional resources, the project manager should work directly with the development managers for resource allocation. If trade offs are required on one manager's resource map in order to book this initiative, the project manager can take a list of trade offs and impacts back to the product management group & Lynn as applicable. If this initiative cannot be booked without impacting multiple resource maps the project manager will then need to raise this issue as an agenda item for the Thursday planning meetings.
Within the Thursday planning meeting such issues are discussed that cannot be resolved offline as well as new initiatives, escalations, etc. Development managers are present and decisions regarding booking, tradeoffs, etc can be made during the meeting. Often times decisions regarding VP or BU input are listed as action items to be resolved shortly after each meeting. The results of each meeting are published and the Tracker tool updated to reflect the decisions made.
When components aren't complete for an initiative, Project Managers should work with Global Product Planning to get the remaining components added. Once we know what we need and how many train seats we can work on booking.

#6. How eBay makes money:
When you sell an item on the site, eBay takes a cut of the profits you make
eBay fees:
Insertion Fees
Final value fees
Reserver fees
Buy it now fees
Listing upgrade fees
eBay Picture service fees
Seller Tool fees
Ad Format Fees
eBay Motors Fees
eBay Stores Fees
Real Estate Fees
PayPal Fees
Paying your eBay Seller's Fees
Invoicing Procedures and Payments

eBay’s Info
• Confirmed Registered Users — eBay cumulative confirmed registered users at the end of Q1-06 totaled 192.9 million, representing a 31% increase over the 147.1 million users reported at the end of Q1-05.
• Active Users — eBay active users, the number of users on the eBay platform who bid, bought, or listed an item within the previous 12-month period, increased to a record 75.4 million in Q1-06, a 25% increase over the 60.5 million active users reported in Q1-05.
• Listings — eBay new listings totaled a record 575.4 million in Q1-06, 33% higher than the 431.8 million new listings reported in Q1-05.
• Gross Merchandise Volume (GMV) — eBay GMV, the total value of all successfully closed items on eBay’s trading platforms, was $12.5 billion in Q1-06, representing an 18% year-over-year increase from the $10.6 billion reported in Q1-05. Excluding the impact of foreign currency translation, Q1-06 GMV increased 22% year over year.
• Fixed Price Trading — eBay’s fixed price trading contributed approximately $4.3 billion or 34% of total GMV during Q1-06, primarily from eBay’s “Buy It Now” feature.
• eBay Stores — At the end of Q1-06, eBay hosted approximately 486,000 stores worldwide, with approximately 247,000 stores hosted on the US site.

EBay reported record consolidated net revenues of $1.390 billion in Q1-06, representing a growth rate of 35% year over year which is primarily due to continued Marketplaces and PayPal growth. Net revenues were negatively impacted by foreign currency translation of approximately $50.2 million in Q1-06 as compared to Q1-05. On a sequential basis, consolidated net revenues were positively impacted by foreign currency translation in Q1-06 by approximately $8.3 million.

#7: What is eBay affiliate program?
Answer: eBay affiliate program drive ACRU's (ACRU – Active Confirmed Registered Users (bid, list, or buy within 12 months). The eBay Affiliate Program pays Internet publishers, Web masters, and other online partners to drive new users to eBay. Affiliates promote eBay with banners, text links, and other innovative tools, such as the Editor Kit and the Flexible Destination Tool. In return, they receive commissions for driving new users as well as bids and "Buy It Now" purchases. Affiliates earn from $5.00 to $13.00 for each new active user and from $0.05 to $0.09 for each bid or "Buy It Now" transaction. Currently, the top 25 affiliates in the program average above $100,000 in monthly commissions.
Joining the eBay Affiliate Program is free.

2006-05-12T17:02:00.000-07:00

PM interview prep material:

1. Study all the eBay site related information.
2. What are the benefits of all the features.
3. Compare the features of eBay, Yahoo, Google, MSN, Amazon
4. What are the measurement metrics
5. What are the current issues.

Resources:
1. Study the following blogs:
EBay Blogs
Jason Steinhorn
eBay Strategies
Google Info
Will Hsu

2. Study Amazon, Google and Yahoo related blogs

2006-05-08T23:36:00.000-07:00

Interview preparation:

Java:
1. Effective Java
2. The Complete Ref
3. Java Almanac
4. Java Forum at http://www.javaworld.com/javaforums/ubbthreads.php?Cat=2&C=2
5. Concurrent Programming in Java
6. Reflection
7. Regular expression

C++
1. Scott Mayor: Effective C++
2. C++ FAQ
3. C++ Programming with design pattern
4. STL basics
5. Object created in the heap vs the object created in the stack.
6. Heap fragmentation and Stack overflow
7. Thread locks: Semaphore, Mutex
8. Copy constructor and Operator overloading
9. Virtual destructor
10. Diff between new, malloc and delete
11. DataStructure: heap, stack
12. Sorting algorithms
13. Multiple inheritence and issues with multiple inheritence.
14. Issues with delete this
15. Is-a and has-a relationship
16. Inhertance vs aggregation

OS/Linux:
1. Command and debbuging.

DB
1. MySQL
2. Nornalization, Indexing, Inner and Outer join

Data Structure:
1. Array, Link List, Vector, Queue, Trees (B/Binary), Hashtable, Hash Map
2. How to traverse a tree.
3. Hashtable: Hashing function, Linear probing

Sorting and Searching:
1. Bubble sort, Shell sort, binary sort, Heap sort, Merge sort
2. Write a program to merge a sorted list.

Misl:
1. Threading Models
2. Thread signalling
3. Sync mechanism: Mutex/Semaphore

2006-05-02T00:52:00.000-07:00

GMAT Prep Tips and feedback from others
1. Following post is by By Twinsplitter at:
http://www.urch.com/forums/just-finished-my-gmat/26097-790-q50-v51-4.html

Haha at first I thought exactly the same thing, especially because I knew that I didn't have any conceptual problems with the stuff on the test and so it must have been a stupid mistake. But then again, I can never manage to make it through an entire quant section without making a stupid mistake, so I wasn't really surprised. What did surprise me tho is that I did better in Verbal than in quant, as quant has always been my strength. But anyways, it's probably a good thing I missed 800 since Stanford takes some sick sort of pride in the fact that they rejected every 800 applicant last year. Still, I do agree that this site will see an 800 soon, especially if Grey ever takes the test again

Disclaimer:I'm sorry if this post is a bit convoluted or too long, I just figured that since many people (especially those new to the site) use these debriefings as a guide, I would put a lot of the great resources from
this site together in one, easy to find spot for them and for everyone else on this site. However, I have tried to make the transition between each section clear (by using boldface), so that if you want to only find my advice on particular sections then it will be easier.
Disclaimer #2: Before I get started on prep strategy, I want to note that I took the LSAT before I took the GMAT, and thus while it may seem like I have not prepped much for CR and RC, it is because I felt that prepping for the LSAT was more than sufficient prep for these two sections. "But I'm not taking the LSAT, so how does this advice help me" you ask? Read on...

Starting Out:
Originally, I had planned to start prepping for my GMAT as soon as I finished the LSAT, which was in early February (in fact I think it was February 12th, exactly 3 months before my GMAT). However, I was exhausted after prepping for the LSAT, and so I decided to wait until I was finished with Winter quarter
finals in mid March.
I had already been frequenting this site for quite some time at that point, and so I knew that starting off with PowerPrep was a great way to know your standing. I took PP1 and the results were: 710 (q47, v40)

Upon looking at the questions I missed, I realized that in quantitative, as is the case for most people, I was mostly hurt by stupid mistakes. However, I had finished that section 15 minutes early, and I knew that if I properly distributed that extra time then I would be in much better shape. Nonetheless, I realized that I was more rusty than I would like in some areas, and so I decided that quant would be the first area I would work on.
In verbal on PP1, I did not get any CR or RC questions wrong. Yup, that's right, I dropped to a v40 SOLELY based on SC. Needless to say, I realized SC was a big weakness of mine that I needed to work on. However, I
think that SC is probably the easiest section to improve your skills in, as a large percentage of it is just memorizing the necessary rules.

My General View on Prep:
I liken prepping for these tests to an athlete preparing for the season. Rather than sort of work each muscle each day, they specifically target one muscle at a time, spending one day doing bicep only workouts, another doing chest workouts, etc. In the same way, I believe that you should target each specific aspect of the test, concentrating on it and really getting in the mode for it, then moving onto the next type of question. However, when you move on, still do 10 questions a day for each previous section you've done. So, for example, if you start off with quant, then two weeks later you focus on SC while doing 10 quant questions a day. Then, when you move on to CR, you do 10 quant questions and 10 SC questions a day, while still keeping your main focus on CR. Note that using this method, you will be spending progressively more time as you get closer to the test, which is probably a good idea anyways.

I think that your knowledge of each subject will become much more solid in this way than it will in the wishy washy way of just doing a little bit of everything all the time. Then, once you start getting closer to the test (i.e. perhaps two weeks before), and after you've targeted each specific section and feel you're sufficiently prepared, then just work on all of them together, the same way an athlete starts doing more general stuff rather than working out once he/she gets closer to game day.

How to Decide Which Aspects to Target First and For How Long:
I believe that, in general, 2 weeks on a specific subject will give you an absolutely solid grasp on it. However, if there are some sections that you feel need more work than others (i.e. if you're strong in CR but weak in SC), then you could spend only one week on the one you're strong at and 3 weeks on your weakness.

In my opinion, it is best to put quant first for two reasons:
1) this site has a lot of great quant questions/resources, and it's easier to utilize them if you're caught up and fresh in quant,
2) Quant is the easiest to keep fresh by doing a few problems a day, so if you put it in the beginning then you still probably won't forget most of it by the time the test comes around.
As far as what to put second, I believe that it is best to put your biggest weakness in verbal second. Why? Because the topics you put near the beginning will be the ones you get the most practice on, since you'll spend 2 weeks targeting them and then will also do 10 questions a day in these topics from
then on.

In other words, here's the prep plan I would recommend to most people:
Quant (2 weeks)
Biggest Verbal Weakness (2-3 weeks)
2nd Biggest Verbal Weakness (2 weeks)
Verbal Strength (1-2 weeks)
All Types of Questions, General Prep, and Practice Tests (2 weeks)
For a total of about 10 weeks.

My own prep was a little different from my recommended, namely in that I didn't prep for CR and RC and thus only targeted two types of questions (quant and SC). However, as I said before, I basically had already targeted CR and RC by preparing for the LSAT.

My prep went as follows (spread over 8 weeks, with two weeks of non-prepping because I had midterms):
Quant (2 weeks)
SC (2 weeks)
General Prep (2 weeks)

While I certainly spent a good amount of time preparing for this test, I didn't do some amazing number of hours (i.e. Ursula's 200 hours). I did about an hour a day on weekdays (not including time spent on TestMagic, which I found to be a great way to procrastinate!), and around 5 hours a day on weekends for a total of about 90 hours. However, if you include time spent on CR and RC for the LSAT, which was about 60 hours, then it totals to 150 hours. I really would have liked to spent more time preparing, but I knew it was impossible, since the University of Chicago is famous for its enjoyment in torturing undergraduates with a ridiculous amount of work (the school's nickname is "where fun comes to die", or "the level of hell daunte forgot").
Note: Any time I found some helpful information on this site, I copy and pasted it into a word document. In general I think this is a good way to keep track of all of the important stuff you see on the site. And, because I did that, now I have a ton of stuff to share with you guys (see resources for each section).

How I Targeted Each Section

Quant:
General Strategy: My prep for quant consisted of three parts (in this order):
1) Going through Kaplan's Math Workbook, underlining all of the important concepts, making notecards of these concepts, and doing the practice problems to strengthen these concepts.
2) Scouring TestMagic for all of the great resources that I knew it had on quant, and making notecards of the concepts in these resources. (resources listed below).
3) Doing tons of quant problems from my many question sources (sources listed below).

I think the most important thing in quant is knowing how to set up an equation from a word problem. If you can do this, you will get 95% of your quant questions right, guaranteed. How can you get good at this? Through practice.
See my list of sources of quant questions below to see where you can get practice at this.

Probably my biggest weakness starting out in quant was number theory, as I believe is the case for many people. My advice on cracking this type of question would be to do several of these problems, because it's really just the kind of thing that you get better at with practice. There are several great number theory problems on this site, as well as in the sources I'll list below. As you do more of them, you just get a knack for knowing how to go at it.

Here's how I went at number theory problems: First, I would try to use mathematical logic to lead me to the correct answer. Most of the time, this would work, and I would pretty much know what kind of numbers are relevant to the question (i.e. negative fractions, positive intergers). I would then think what would occur with these types of numbers, and this would lead to the answer.

However, if I was unable to crack it using mathematical logic, I would simply try to plug numbers in, using Alakshma's strategy of plugging in (-2, -1, -0.5, 0, 0.5, 1, 2).

Generally, I would come to the answer sooner or later.
For permutations and combinations, I initially spent way too much time on them (hence the plethora of probability and comb/perm links below) but then realized that I need to take everyone's advice and stop paying attention to them so much. All of you would be well advised to do the same! There's much more
important things to spend your time on.

For Statistics, as I said, I just took a class on it last quarter and thus didn't prepare much for it. However, even had I not taken the class, I still feel that most statistics on the GMAT is fairly easy, perhaps because they know
that most people don't really know the concepts in statistics. So just learn the basic concepts (i.e. what a median is, the fact that standard deviation measures spread, how it is calculated--although I doubt you'll actually have to calculate it, it is helpful to understand how to get it when trying to analyze
what it means).

Sources of Quant Questions:
1) Kaplan's Math Workbook did every problem in the book
2) Kaplan 2005 (with the CD) did every problem in the book, as well as all the Problem Solving and Data Sufficiency Tests on the CD. However, I didn't do any of the CAT full length tests, which I'll discuss in practice tests.
3) Official Guide only did the questions categorized as hard bin by this document.
4) I bought Kaplan 800 but never ended up having enough time to get to it. However, I've heard great things about it, and would thus recommend getting it.
5) TestMagic--Quant Section. Like Grey said, if you search all topics started by Nuthan in the DS section, you'll get hundreds of DS questions to practice on. Also, searching posts made by Lego, Grey, and Shaq can be a great way to find the best problems on this site, and it will also show you how the math geniuses approach
problems. But while we're on the subject of math geniuses--don't be intimidated if they come up with
brilliant solutions you never would have thought of. Many of the quant questions on this site are much more difficult than what you'll see on the real GMAT.

Quant Resources (note--I probably shouldn't even include all the comb/perm stuff on here b/c I know you guys will spend too much time on it then , but I figure if you're going to waste your time on it, might as well have an easier time finding the stuff ):

Must Have:
Great Math Review
Arithmetic and Geometric Progressions
Overview of Combinations
Overview of Permutations
HCF and LCM Stuff -- The beginning is simple, but further down there are some helpful tricks I didn't know about
Venn Diagram
-- check out my post second from the bottom on the first page. Has everything
you need to know about 3 category sets.

Note: For two category sets, it's simply P(AuB) = P(A) + P(B) - P(AnB)

Everything You Need For Prob/Comb/Perm
Compilation Of Prob/Comb/Perm Questions
Compilation of Tough Problems

Also Helpful:
How to do well in quant
Basic info on standard deviation (math reference in Kaplan tells you how to calculate it)
Info on Probability
More Permutations
More Combinations
More Prob/Comb/Perm
Angles and Arcs

Sentence Correction
General Strategy: As I said when discussing my PP1 results, I only got around 65% of these right on my first test. By the time of the test, I averaged 1 wrong out of every 100 questions. Here's how I improved so much:
First thing I did was buy Manhattan GMAT's Sentence Correction Guide. While it's true that, as everyone says,
OG is the bible for practicing verbal, I would say that this book is the bible for learning the rules of SC. This book is so comprehensive it's amazing. I cannot emphasize enough what an important role this book played in achieving my score. Also, the friend I told you about who got a 750 without studying did actually spend a couple of days studying. The only thing he studied was this book, and as a result his verbal score jumped from 40 on PP1 to 44 on the actual GMAT.

Here's how to utilize the book:
First, go through Manhattan GMAT's SC guide, highlighting every important point (which, in my opinion, is almost every point in the book) and then making notecards out of those points. Memorize them every chance you get (I did this whenever I rode the bus). At the end of each chapter, Manhattan GMAT lists a set of problems in OG which test the concept you learned about in that chapter. Doing the problem set knowing what type of error you're looking for will make you adept at noticing that problem.
Then, once you have gone through every chapter in Manhattan GMAT, and done the corresponding problems in OG, do OG again, starting from problem number 1. This time, you won't know what type of error you'll be
looking for, but you'll have become so good by doing the problem sets that you will start noticing that you've gotten MUCH better at SC.
Regarding doing the problems in OG more than once: I remember someone saying in their debriefing that as long as you're not memorizing the answers in OG, you can do the problems over again, and you can also take PP and have it be an accurate predictor. I couldn't agree more. Read the explanations, but don't memorize them, so that you can practice as much as possible on real GMAT questions.
One final note: I never ended up using the 1000 SC doc because I found that repeating OG was enough, but
if you feel like you're running out of questions, there are several great questions in 1000 SC as well as in the FREE ETS paper tests that I'll provide links to later.

Resources for SC:
Spidey's SC Notes
1000 SC's
Grammar Reference Didn't use it myself, but looks pretty comprehensive for anyone who wants to check it out.

Critical Reasoning
General Strategy: The way I approached CR problems was much different than the way Kaplan (and most books) recommend it. Unlike most people, I don't read the question stem before I read the stimulus. Rather, I read the stimulus first, trying to get a thorough understanding so that regardless of what the question is, I'm ready to attack it. I really think that this helped build my logic skills, so that I was better prepared for any kind of CR question than I would have been if I had a more question-type-specific approach. I feel that had I tried to read the question first, I'd be so focused on trying to find the assumption/implication that I wouldn't understand the argument as a whole intricately enough to analyze the answer choices appropriately. One reason I trusted this approach is that TestMasters, the company known for being the best LSAT prep course, recommends it (and the LSAT is 1/2 CR, so you figure an LSAT prep course would be particularly privy to how to approach the problems). However, each person should take the approach they feel is best!

Recommended Prep Approach:
I think that the reason I was so good at CR is because, as I said above, the LSAT is half CR, and its CR questions are MUCH more difficult than those on the GMAT. They are extremely nitpicky, which helps you become very logical and helps you spot the errors in GMAT arguments in a second. Thus, I would recommend buying the
"Next Ten Actual, Official LSAT PrepTests", which contains 500 LSAT CR questions. If you don't want to buy the book but still want a few LSAT questions, download this free LSAT test.
Do those when you're targeting your CR skills, and then start doing the CR in the OG once you start getting closer to the test (just to get used to the GMAT's style of CR). As far as boldfaced questions, I didn't specifically prep for them, although the LSAT contains some questions which are similar (argument structure questions). Like others have said, process of elimination is pretty helpful in the boldface.
For those of you still looking for boldface questions, I heard that akasans has posted a lot of boldfaced CR's on the site.
Resources for CR:
I don't have any, I'm sorry

Reading Comprehension
General Strategy: I don't really have much of a strategy on reading comprehension, I just sort of read it and answer the questions. One thing that I found was that reading on the computer was very easy for me, perhaps because I read articles online all the time. Many people suggest using the economist online, but that costs $$. Instead, check out McKinsey Quarterly, which will help your ability to read on a computer screen, your knowledge of business examples (if you get a business issue on AWA), and will probably help your career too by making you knowledgeable on several business issues!
One thing which I think helped me a lot on both my RC and AWA was the fact that I read the editorial section of the Wall Street Journal every morning on the way to school. It does several things for me:

1) Exposes me to complex arguments similar to those in RC and CR
2) Gives me practice reading on topics which I am often unfamiliar with
3) Keeps me informed, so that I have more real life examples to use in

AWA.
Finally, perhaps my most important piece of advice on RC is to use the RC's that come in that LSAT book (linked above in the CR section) as practice. The LSAT passages are much more complex, and the questions are much more specific, so that you'll be forced to get better at remembering what you read! Use the LSAT book when targeting RC, and then as the test nears, start doing the OG RC's.

Resources for RC-- I'm not sure regarding the quality of any of these because I haven't gone through them, but I did copy good links whenever I saw them in case I needed more practice for RC, so I figured I might as well share
Ten Vocabulary Learning Tips if you feel like not knowing some of the words in the RC's is hindering your
ability to do well (although it's very normal not to know some of them).
More RC Materials
Even More

Analytical Writing Assessment
General Strategy: Spend a couple days before your test thinking of some big fancy words (my words of choice were eludicate, juxtapose, paucity, dearth, and some other ones that I have now forgotten), as well as some real life examples. I have found that if you have 6 real life examples, odds are 3 of them will be moldable (if that's a word) to become relevent to your topic in analysis of an issue. Attached are my

AWA templates (sorry Stormgal, I only know how to attach things in threads!). They are essentially a hybrid of Erin's, Sybersport's, and several other templates that I have found on this site.
As far as prep for AWA, I didn't have any. I simply checked a couple topics out, thought about what I'd say for them to get my mind in the writing mode, and that's about it. However, if you would like a book to build your
AWA, Spiderman recommended this book which seems like it would be helpful because you can see how others approach it and steal some of their arguments!

Resources for AWA:
Erin's Template for Analysis of an Issue
Template for Analysis of an Argument
Sybersport's (who got a 6.0) Advice
Formatting Rules (makes the grader nice to you!)

More General Resources
There's tons of good (free) stuff I found through TestMagic! Here it is:
All 9 Paper Tests
Calculating Paper Test Scores
OG Softcopy
Free Manhattan GMAT CD
Categorization of OG Questions (I know I've linked to it already, but just wanna make sure everyone gets it, it's really helpful!)
Too many resources to name
Answer Grid that Times You
Prep Strategy Site
Prep Strategy Site #2
Prep Strategy Site #3

Timing:
I didn't put much effort into working on timing, mostly because the LSAT is far more time constrained than the GMAT and I was thus able to work very quickly on everything. In other words, by working in high-pressure, time-constrained situations, my timing got better. Thus, I would recommend doing the same, e.g. only giving yourself 15 minutes to do 10 problems rather than 20 minutes. However, only do this once you know the concepts, because otherwise what's the point of going quickly when you don't even know what it is that you're doing quickly!
I think Kaplan's CD is really good for improving timing in Quant...while giving you only 25 minutes for 20 DS questions may seem ridiculous, it sure makes the actual GMAT, with 2 minutes per question, seem much easier.
Practice Tests:
I know it's really helpful to see what people's practice test scores were so that you know where you stand relative to them. Unfortunately, I don't have many practice scores to give you guys! I knew my timing was alright, and so I felt that doing more problems and learning more concepts was more beneficial for me than doing more practice tests. But again, this is pretty unique to my situation because the LSAT had improved my timing so much. For most people, I would recommend taking SEVERAL practice tests.
Anyways, here's the scores on the tests that I did take:
PP1 (before any prep): 710 (q47, v40)
PP2 (after targeting math and SC): 780 (q50, v47)
Kaplan diagnostic--the one in the book: 700 (q49, v45). Don't know how the hell this score breakup comes out to a 700, but I didn't care b/c I knew Kaplan's tests were horrible.

Day Before the Test:
Unlike most people, I didn't go out to dinner or relax the day before my test. Instead, I did several practice
problems, because I noticed that whenever I would take a couple days off from the GMAT, my mind would get out of the GMAT mindset. So, as I've said earlier, do what you feel best fits your own situation!

Hit Rates:
Problem Solving (in the beginning, when I was making stupid mistakes): 90%
Problem Solving (once I got better at preventing stupid mistakes): 97%
Data Sufficiency (when making stupid mistakes): 85%
Data Sufficiency (once I got better at preventing stupid mistakes): 93%
Sentence Correction (first time around, going category by category as assigned by Manhattan GMAT's book): 95%
Sentence Correction (second time around): 98-99%
Critical Reasoning (did about 80 q's from OG): 95%
Reading Comp: Only ones I did were on the practice tests, and I think my hit rate was around 97%.
Note, however, that pre-LSAT, my CR was around 84% and my RC was 92%, so don't be discouraged if yours are below mine. Also, for SC, remember that my hit rate before Manhattan GMAT was 65% on that one test. So regardless of where you're at, you can get much better by prepping appropriately.

Future Plans
This fall, I am planning on applying to the three top schools which occassionally accept college seniors without work experience: Stanford, Harvard, and Columbia. I am hoping that this GMAT score, my GPA, the fact that my school is pretty good, my extracurriculars, and my internships will be enough to make me part of the 2% of the entering class that these schools accept without work experience. And if not, the University of
Chicago GSB has a special program for undergraduates at the U of C, in which students apply as seniors, and if they are accepted then they get deferred acceptance, working for two years and then returning after that.

2006-05-02T00:36:00.000-07:00

GMAT:

The following are the links that I got from: http://thefamilyguymba.blogspot.com/2005/04/gmat-experince.html

http://www.syvum.com/gmat/http://atheism.about.com/od/logicalfallacies/a/overview.htm http://daveformba.blogspot.com/http://richardbowles.tripod.com/gmat/gmatmenu.htm http://www.test-preps.com/gmat/math_test_sol.php http://novapress.net/gmat/strategies.html http://www.novapress.net/gmat/math.html http://education.kulichki.net/GMAT/math1.html http://www.gmatbuster.org/http://novapress.net/gmat/math.html http://s2s.wharton.upenn.edu/wh-wharton/messages?msg=5423.1 http://geethu.blogspot.com/2004/06/studying-for-gmat.html http://www.crack-gmat.com/gmat-test.htm http://www.testmagic.com/forum/topic.asp?TOPIC_ID=11279 http://www.testmagic.com/forum/forum.asp?FORUM_ID=67 http://www.microedu.com/gmattest/freetest.htm http://mbaleague.blogspot.com/http://mbawire.blogspot.com/2003_06_29_mbawire_archive.html http://www.krysstal.com/binomial.html http://mathforum.org/dr.math/faq/faq.divisibility.html http://www.gmatclub.com/phpbb/viewtopic.php?t=8202 http://gmat.prepedge.com/MBA/GMAT-CAT/questionbank/ http://s2s.wharton.upenn.edu/n/mb/message.asp?webtag=wh-wharton&msg=7849.1 http://education.kulichki.net/GMAT/math.html http://www.800score.com/gmat-home.html http://www.800score.com/guidetc.html http://www.ascenteducation.com/india-mba/iim/cat/questionbank/Archives/April2002/arith1704.shtml http://www.gmattutor.com/tricks2.html http://www.800score.com/guidec8bview1a.html http://www.economist.com/research/StyleGuide/ http://www.sentencecorrection.com/forums/index.php?act=idx http://novapress.net/gmat/data-sufficiency.html http://www.deltacourse.com/

Some additional links:
1. RC resource: http://www.aldaily.com/
2. Verbal and Analytical question bank: http://www.urch.com/forums/archive/index.php/f-111.html
3. Score Top: http://www.scoretop.com/
4. Deltacourse use debankur as a login name and usual password: http://www.deltacourse.com/gmat/gmat-login.asp

2006-05-02T00:14:00.000-07:00

Technical Questions For Computer Science Programmers

1. Given a rectangular (cuboidal for the puritans) cake with a rectangular piece removed (any size or orientation), how would you cut the remainder of the cake into two equal halves with one straight cut of a knife ?

2. You're given an array containing both positive and negative integers and required to find the subarray with the largest sum (O(N) a la KBL). Write a routine in C for the above.

3. Given an array of size N in which every number is between 1 and N, determine if there are any duplicates in it. You are allowed to destroy the array if you like. [ I ended up giving about 4 or 5 different solutions for this, each supposedly better than the others ].

4. Write a routine to draw a circle (x ** 2 + y ** 2 = r ** 2) without making use of any floating point computations at all. [ This one had me stuck for quite some time and I first gave a solution that did have floating point computations ].

5. Given only putchar (no sprintf, itoa, etc.) write a routine putlong that prints out an unsigned long in decimal. [ I gave the obvious solution of taking % 10 and / 10, which gives us the decimal value in reverse order. This requires an array since we need to print it out in the correct order. The interviewer wasn't too pleased and asked me to give a solution which didn't need the array ].

6. Give a one-line C expression to test whether a number is a power of 2. [No loops allowed - it's a simple test.]

7. Given an array of characters which form a sentence of words, give an efficient algorithm to reverse the order of the words (not characters) in it.

8. How many points are there on the globe where by walking one mile south, one mile east and one mile north you reach the place where you started.

9. Give a very good method to count the number of ones in a 32 bit number. (caution: looping through testing each bit is not a solution).

10. What are the different ways to say, the value of x can be either a 0 or a 1. Apparently the if then else solution has a jump when written out in assembly. if (x == 0) y=0 else y =x
There is a logical, arithmetic and a datastructure soln to the above problem.
11. Reverse a linked list.
12. Insert in a sorted list
13. In a X's and 0's game (i.e. TIC TAC TOE) if you write a program for this give a gast way to generate the moves by the computer. I mean this should be the fasteset way possible. The answer is that you need to store all possible configurations of the board and the move that is associated with that. Then it boils down to just accessing the right element and getting the corresponding move for it. Do some analysis and do some more optimization in storage since otherwise it becomes infeasible to get the required storage in a DOS machine.

14. I was given two lines of assembly code which found the absolute value of a number stored in two's complement form. I had to recognize what the code was doing. Pretty simple if you know some assembly and some fundaes on number representation.

15. Give a fast way to multiply a number by 7.

16. How would go about finding out where to find a book in a library. (You don't know how exactly the books are organized beforehand).

17. Linked list manipulation.

18. Tradeoff between time spent in testing a product and getting into the market first.

19. What to test for given that there isn't enough time to test everything you want to.

20. First some definitions for this problem: a) An ASCII character is one byte long and the most significant bit in the byte is always '0'. b) A Kanji character is two bytes long. The only characteristic of a Kanji character is that in its first byte the most significant bit is '1'.
Now you are given an array of a characters (both ASCII and Kanji) and, an index into the array. The index points to the start of some character. Now you need to write a function to do a backspace (i.e. delete the character before the given index).

21. Delete an element from a doubly linked list.

22. Write a function to find the depth of a binary tree.

23. Given two strings S1 and S2. Delete from S2 all those characters which occur in S1 also and finally create a clean S2 with the relevant characters deleted.
24. Assuming that locks are the only reason due to which deadlocks can occur in a system. What would be a foolproof method of avoiding deadlocks in the system.
25. Reverse a linked list.
26. Write a small lexical analyzer - interviewer gave tokens. expressions like "a*b" etc.
27. Besides communication cost, what is the other source of inefficiency in RPC?
(answer : context switches, excessive buffer copying). How can you optimise the communication? (ans : communicate through shared memory on same machine, bypassing the kernel _ A Univ. of Wash. thesis)
28. Write a routine that prints out a 2-D array in spiral order!
29. How is the readers-writers problem solved? - using semaphores/ada .. etc.
30. Ways of optimizing symbol table storage in compilers.
31. A walk-through through the symbol table functions, lookup() implementation etc - The interv. was on the Microsoft C team.
32. A version of the "There are three persons X Y Z, one of which always lies"..
etc..
33. There are 3 ants at 3 corners of a triangle, they randomly start moving towards another corner.. what is the probability that they don't collide.
34. Write an efficient algo and C code to shuffle a pack of cards.. this one was a feedback process until we came up with one with no extra storage.
35. The if (x == 0) y = 0 etc..
36. Some more bitwise optimization at assembly level
37. Some general questions on Lex Yacc etc.
38. Given an array t[100] which contains numbers between 1..99. Return the duplicated value. Try both O(n) and O(n-square).
39. Given an array of characters. How would you reverse it. ? How would you reverse it without using indexing in the array.
40. GIven a sequence of characters. How will you convert the lower case characters to upper case characters. ( Try using bit vector - sol given in the C lib -> typec.h)
41. Fundas of RPC.
42. Given a linked list which is sorted. How will u insert in sorted way.
43. Given a linked list How will you reverse it.
44. Tell me the courses you liked and why did you like them.
45. Give an instance in your life in which u were faced with a problem and you tackled it successfully.
46. What is your ideal working environment. ( They usually to hear that u can work in group also.)
47. Why do u think u are smart.
48. Questions on the projects listed on the Resume.
49. Do you want to know any thing about the company.( Try to ask some relevant and interesting question).
50. How long do u want to stay in USA and why?
51. What are your geographical preference?
52. What are your expecctations from the job.
53. Give a good data structure for having n queues ( n not fixed) in a finite memory segment. You can have some data-structure separate for each queue. Try to use at least 90% of the memory space.
54. Do a breadth first traversal of a tree.
55. Write code for reversing a linked list.
56. Write, efficient code for extracting unique elements from a sorted list of array. e.g. (1, 1, 3, 3, 3, 5, 5, 5, 9, 9, 9, 9) -> (1, 3, 5, 9).
57. C++ ( what is virtual function ? what happens if an error occurs in constructor or destructor. Discussion on error handling, templates, unique features of C++. What is different in C++, ( compare with unix).
58. Given a list of numbers ( fixed list) Now given any other list, how can you efficiently find out if there is any element in the second list that is an element of the first list (fixed list).
59. GIven 3 lines of assembly code : find it is doing. IT was to find absolute value.
60. If you are on a boat and you throw out a suitcase, Will the level of water increase.
61. Print an integer using only putchar. Try doing it without using extra storage.
62. write C code for deleting an element from a linked listy traversing a linked list efficient way of elimiating duplicates from an array
63. what are various problems unique to distributed databases
64. declare a void pointer a) void *ptr;
65. make the pointer aligned to a 4 byte boundary in a efficient manner a) assign the pointer to a long number and the number with 11...1100 add 4 to the number
66. what is a far pointer (in DOS)
67. what is a balanced tree
68. given a linked list with the following property node2 is left child of node1, if node2 < node1 els, it is the right child.
O P O A O B O C
How do you convert the above linked list to the form without disturbing the property. Write C code for that.
O P O B / \ / \ / \ O ? O ?
determine where do A and C go
69. Describe the file system layout in the UNIX OS a) describe boot block, super block, inodes and data layout
70. In UNIX, are the files allocated contiguous blocks of data a) no, they might be fragmented how is the fragmented data kept track of a) describe the direct blocks and indirect blocks in UNIX file system
71. Write an efficient C code for 'tr' program. 'tr' has two command line arguments. They both are strings of same length. tr reads an input file, replaces each character in the first string with the corresponding character in the second string. eg. 'tr abc xyz' replaces all 'a's by 'x's, 'b's by 'y's and so on. a) have an array of length 26. put 'x' in array element corr to 'a' put 'y' in array element corr to 'b' put 'z' in array element corr to 'c' put 'd' in array element corr to 'd' put 'e' in array element corr to 'e' and so on.
the code while (!eof) { c = getc(); putc(array[c - 'a']); }
72. what is disk interleaving
73. why is disk interleaving adopted
74. given a new disk, how do you determine which interleaving is the best a) give 1000 read operations with each kind of interleaving determine the best interleaving from the statistics
75. draw the graph with performace on one axis and 'n' on another, where 'n' in the 'n' in n-way disk interleaving. (a tricky question, should be answered carefully)
76. I was a c++ code and was asked to find out the bug in that. The bug was that he declared an object locally in a function and tried to return the pointer to that object. Since the object is local to the function, it no more exists after returning from the function. The pointer, therefore, is invalid outside.
77. A real life problem - A square picture is cut into 16 sqaures and they are shuffled. Write a program to rearrange the 16 squares to get the original big square.

2006-05-02T00:12:00.000-07:00

Programming Questions:

This is a summary of the questions I got in 9 in-person interviews with 5 companies and about 10 phone screens 8/02-11/02.
The interviews were pretty evenly split between very large, large, and startup-sized tech companies.

The good news is that interview question repertoire is generally very limited.
The Programming Interviews Exposed
book covered or helped on probably 60-70% of questions I got. Well worth the
$20.
A) Linked Lists
This is an extremely popular topic. I've had linked lists on every interview.You must be able to produce simple clean linked list implementations quickly.
1. Implement Insert and Delete for
- singly-linked linked list
- sorted linked list
- circular linked list
int Insert(node** head, int data)int Delete(node**
head, int deleteMe)

2. Split a linked list given a pivot value
void Split(node* head, int pivot, node** lt, node** gt)

3. Find if a linked list has a cycle in it. Now do it without marking nodes.

4. Find the middle of a linked list. Now do it while only going through the list once. (same solution as finding cycles)

B) Strings
1. Reverse words in a string (words are separated by one or more spaces). Now do it in-place. By far the most popular string question!

2. Reverse a string

3. Strip whitespace from a string in-place
void StripWhitespace(char* szStr)

4. Remove duplicate chars from a string ("AAA BBB" -> "A B")
int RemoveDups(char* szStr)

5. Find the first non-repeating character in a string:("ABCA" -> B )
int FindFirstUnique(char* szStr)

C) More Advanced Topics:
You may be asked about using Unicode strings. What the interviewer is usually looking for is:
each character will be two bytes (so, for example, char lookup table you may have allocated needs to be expanded from 256 to 256 * 256 = 65536 elements)
- that you would need to use wide char types (wchar_t instead of char)
- that you would need to use wide string functions (like wprintf instead of printf)
Guarding against being passed invalid string pointers or non nul-terminated strings (using walking through a string and catching memory exceptions

D) Binary Trees
Implement the following functions for a binary tree:
- Insert
- PrintInOrder
- PrintPreOrder
- PrintPostOrder

Implement a non-recursive PrintInOrder

E) Arrays
1. You are given an array with integers between 1 and 1,000,000. One integer is in the array twice. How can you determine which one? Can you think of a way to do it using little extra memory.

2. You are given an array with integers between 1 and 1,000,000. One integer is missing. How can you determine which one? Can you think of a way to do it while iterating through the array only once. Is overflow a problem in the solution? Why not?

3. Returns the largest sum of contiguous integers in the arrayExample: if the input is (-10, 2, 3, -2, 0, 5, -15), the largest sum is 8
int GetLargestContiguousSum(int* anData, int len)

4. Implement Shuffle given an array containing a deck of cards and the number of cards. Now make it O(n).
Return the sum two largest integers in an array.
int SumTwoLargest(int* anData, int size)

5. Sum n largest integers in an array of integers where every integer is between 0 and 9int SumNLargest(int* anData, int size, int n)

F) Queues
Implement a Queue class in C++ (which data structure to use internally? why? how to notify of errors?)

G) Other

1. Count the number of set bits in a byte/int32 (7 different solutions)

2. Difference between heap and stack? Write a function to figure out if stack grows up or down.

3. SQL query to select some rows out of a table (only because I had SQL on the resume)

4. Open a file as securely as possible (assume the user is hostile -- list all the nasty things that could happen and checks you would have to do to)

5. Implement a function to return a ratio from a double (ie 0.25 -> 1/4). The function will also take a tolerance so if toleran ce is .01 then FindRatio(.24, .01) -> 1/4int FindRatio(double val, double tolerance,
int& numerator, int& denominator)

6. Write a program that tests whether a floating point number is zero. (Hint: You shouldn't generally use the equality operator == with floating point numbers, since floating point numbers by nature are hard to match exactly. Instead, test whether the number is close to zero.)

public class FloatTest {
public static void main(String[] args) {
float f = 100.0f;
float MAX = 0.001f;
float MIN = -MAX;
System.out.print(String.valueOf(f));
if ((f <> MIN)) {
System.out.println(" is pretty darn close to 0.");
} else {
System.out.println(" is not close to 0.");
}
}
}

F) Puzzles

1. You have 2 supposedly unbreakable light bulbs and a 100-floor building. Using fewest possible drops, determine how much of an impact this type of light bulb can withstand. (i.e. it can withstand a drop from 17th
floor, but breaks from the 18th).Note that the ever-popular binary search will give you a worst case of 50 drops. You should be able to do it with under 20.

2. There are n gas stations positioned along a circular road. Each has a limited supply of gas. You can only drive clockwise around the road. You start with zero gas. Knowing how much gas you need to get from each gas station to the next and how much gas you can get at each station, design an algorithm to find the gas station you need to start at to get all the way around the circle.

3. Out of 10 coins, one weighs less then the others. You have a scale. How can you determine which one weighs less in 3 weighs? Now how would you do it if you didn't know if the odd coin weighs less or more?

4. What is the next line in the following sequence:11121Answer: it's 1211 and the next is 111221

G) Design Questions

1. How would you design a server that has to process a fair number of good number of requests a second. What if you didn't know how many requests you'd be getting? What if requests had different priorities? (I always think of the Apache design for this question)

2. Design malloc and free. (give up? see how G++ malloc works or this page for more examples)

3. Design an elevator control system. Don't forget buttons on every floor and supporting multiple elevators. (What objects/methods/properties/how components communicate)

4. Design a chess game (what objects? what methods? which data where? how will it work?)

5. Design a deck of cards class (object/methods/data)

6. How would you design the infrastructure front half of a very large web ecommerce site? what if it was very personalized? (how sessions are handled? where and what you can cache? how to load-balance?)

H) Concurrency

1. Difference between Mutexes and Critical Sections?

2. What are Reentrant Locks? Implement a Reentrant Lock with Mutexes.

3. Implement a thread-safe class that will read/write to/from a buffer

TSBuffer::TSBuffer(int size)
int TSBuffer::Read(char* buff, int max_size)
int TSBuffer::Write(char* buff, int size)

I) Windows-specific Questions

1. What is the IUnknown COM interface?
2. Synchronization primitives available in Windows (see MSDN documentation)
3. Basic structure of a Win32 program (WinMain, Message processing)

J) Networking

1. Difference between TCP and UDP? When would you want to use one over the other?
2. How would approach guaging performance of webpages/parts on a very large website?

K) Questions you are unlikely to get unless you claim a lot of IP experience

1. How does traceroute work?
2. How does path MTU discovery work?
3. How can one poison a BGP peer?

L) Non-Technical Questions

All of the following are very common. It's best to have canned answers.
1. What do you want to do?
2. Describe your perfect job?
3. How did your interview go? How did you like the group you interviewed with?
4. Rate your C++ proficiency on the scale of 1 to 10.
5. What have you been up to since you were laid off or finished school?
6. Why do you want to work at X?
7. What reservations do you have working at X?
8. Do you like working alone or in a group?
9. Discuss your greatest accomplishment over the last couple years.
10. Discuss one big problem you solved in a work/school project.
11. How do you handle conflict in a group?
12. How much do you want to make? How much did you make at your previous position?

M) Marketing Questions
Questions for Marketing candidates.

1. How would you market a [specific product this company makes] to a [specific population you are familiar with]? (Example: How would you market Word to college students?)
2. How would you expand a [business you are familar with]?

Links:
The best book for tech interviews, in my opinion - "Programming Interviews Exposed"
Joel On Software article about resumes - must read
Joel On Software techInterview section - more questions and answers
Seven Questions Employees Should Ask Before Joining a Startup

Programming Books:

The original and best C reference by the creators of C:

C Programming Language (2nd Edition) by Brian W. Kernighan
and
Dennis M. Ritchie

The original and best C++ reference by the creator of
C++:The C++ Programming Language (Special 3rd Edition)
by
Bjarne Stroustrup (creator of C++)

2006-05-02T00:04:00.000-07:00

Design Pattern:

1. Java design pattern: http://www.allapplabs.com/java_design_patterns/facade_pattern.htm

2006-05-02T00:00:00.000-07:00

Database questions:

DB2 Questions:
Q:
What is SQL?
A:
SQL stands for 'Structured Query Language'.

TOP
Q:
What is SELECT statement?
A:
The SELECT statement lets you select a set of values from a table in a database. The values selected from the database table would depend on the various conditions that are specified in the SQL query.

TOP
Q:
How can you compare a part of the name rather than the entire name?
A:
SELECT * FROM people WHERE empname LIKE '%ab%'Would return a recordset with records consisting empname the sequence 'ab' in empname .

TOP
Q:
What is the INSERT statement?
A:
The INSERT statement lets you insert information into a database.

TOP
Q:
How do you delete a record from a database?
A:
Use the DELETE statement to remove records or any particular column values from a database.

TOP
Q:
How could I get distinct entries from a table?
A:
The SELECT statement in conjunction with DISTINCT lets you select a set of distinct values from a table in a database. The values selected from the database table would of course depend on the various conditions that are specified in the SQL query. ExampleSELECT DISTINCT empname FROM emptable

TOP
Q:
How to get the results of a Query sorted in any order?
A:
You can sort the results and return the sorted results to your program by using ORDER BY keyword thus saving you the pain of carrying out the sorting yourself. The ORDER BY keyword is used for sorting.SELECT empname, age, city FROM emptable ORDER BY empname

TOP
Q:
How can I find the total number of records in a table?
A:
You could use the COUNT keyword , exampleSELECT COUNT(*) FROM emp WHERE age>40

TOP
Q:
What is GROUP BY?
A:
The GROUP BY keywords have been added to SQL because aggregate functions (like SUM) return the aggregate of all column values every time they are called. Without the GROUP BY functionality, finding the sum for each individual group of column values was not possible.

TOP
Q:
What is the difference among "dropping a table", "truncating a table" and "deleting all records" from a table.
A:
Dropping : (Table structure + Data are deleted), Invalidates the dependent objects ,Drops the indexes
Truncating: (Data alone deleted), Performs an automatic commit, Faster than delete
Delete : (Data alone deleted), Doesn’t perform automatic commit

TOP
Q:
What are the Large object types suported by Oracle?
A:
Blob and Clob.

TOP
Q:
Difference between a "where" clause and a "having" clause.
A:
Having clause is used only with group functions whereas Where is not used with.

TOP
Q:
What's the difference between a primary key and a unique key?
A:
Both primary key and unique enforce uniqueness of the column on which they are defined. But by default primary key creates a clustered index on the column, where are unique creates a nonclustered index by default. Another major difference is that, primary key doesn't allow NULLs, but unique key allows one NULL only.

TOP
Q:
What are cursors? Explain different types of cursors. What are the disadvantages of cursors? How can you avoid cursors?
A:
Cursors allow row-by-row prcessing of the resultsets.
Types of cursors: Static, Dynamic, Forward-only, Keyset-driven. See books online for more information.
Disadvantages of cursors: Each time you fetch a row from the cursor, it results in a network roundtrip, where as a normal SELECT query makes only one rowundtrip, however large the resultset is. Cursors are also costly because they require more resources and temporary storage (results in more IO operations). Furthere, there are restrictions on the SELECT statements that can be used with some types of cursors.
Most of the times, set based operations can be used instead of cursors.

TOP
Q:
What are triggers? How to invoke a trigger on demand?
A:
Triggers are special kind of stored procedures that get executed automatically when an INSERT, UPDATE or DELETE operation takes place on a table.
Triggers can't be invoked on demand. They get triggered only when an associated action (INSERT, UPDATE, DELETE) happens on the table on which they are defined.
Triggers are generally used to implement business rules, auditing. Triggers can also be used to extend the referential integrity checks, but wherever possible, use constraints for this purpose, instead of triggers, as constraints are much faster.
Q:
What is a join and explain different types of joins.
A:
Joins are used in queries to explain how different tables are related. Joins also let you select data from a table depending upon data from another table.
Types of joins: INNER JOINs, OUTER JOINs, CROSS JOINs. OUTER JOINs are further classified as LEFT OUTER JOINS, RIGHT OUTER JOINS and FULL OUTER JOINS.

TOP
Q:
What is a self join?
A:
Self join is just like any other join, except that two instances of the same table will be joined in the query.

Oracle Questions:

1. What are the components of Physical database structure of Oracle Database?.
ORACLE database is comprised of three types of files. One or more Data files, two are more Redo Log files, and one or more Control files.
2. What are the components of Logical database structure of ORACLE database?
Tablespaces and the Database's Schema Objects.
3. What is a Tablespace?
A database is divided into Logical Storage Unit called tablespaces. A tablespace is used to grouped related logical structures together.
4. What is SYSTEM tablespace and When is it Created?
Every ORACLE database contains a tablespace named SYSTEM, which is automatically created when the database is created. The SYSTEM tablespace always contains the data dictionary tables for the entire database.
5. Explain the relationship among Database, Tablespace and Data file.
Each databases logically divided into one or more tablespaces One or more data files are explicitly created for each tablespace.
6. What is schema?
A schema is collection of database objects of a User.
7. What are Schema Objects ?Schema objects are the logical structures that directly refer to the database's data. Schema objects include tables, views, sequences, synonyms, indexes, clusters, database triggers, procedures, functions packages anddatabase links.
8. Can objects of the same Schema reside in different tablespaces.?Yes.
9. Can a Tablespace hold objects from different Schemes ?Yes.
10. what is Table ?A table is the basic unit of data storage in an ORACLE database. The tables of a database hold all of the user accessible data. Table data is stored in rows and columns.
11. What is a View ?
A view is a virtual table. Every view has a Query attached to it. (The Query is a SELECT statement that identifies the columns and rows of the table(s) the view uses.)
12. Do View contain Data ?
Views do not contain or store data.
13. Can a View based on another View ?
Yes.
14. What are the advantages of Views ?
Provide an additional level of table security, by restricting access to a predetermined set of rows and columns of a table.Hide data complexity.Simplify commands for the user.Present the data in a different perpecetive from that of the base table.Store complex queries.
15. What is a Sequence ?
A sequence generates a serial list of unique numbers for numerical columns of a database's tables.
16. What is a Synonym ?
A synonym is an alias for a table, view, sequence or program unit.
17. What are the type of Synonyms?
There are two types of Synonyms Private and Public.
18. What is a Private Synonyms ?
A Private Synonyms can be accessed only by the owner.
19. What is a Public Synonyms ?
A Public synonyms can be accessed by any user on the database.
20. What are synonyms used for ?
Synonyms are used to : Mask the real name and owner of an object.Provide public access to an objectProvide location transparency for tables,views or program units of a remote database.Simplify the SQL statements for database users.
21. What is an Index ?
An Index is an optional structure associated with a table to have direct access to rows,which can be created to increase the performance of data retrieval. Index can be created on one or more columns of a table.
22. How are Indexes Update ?
Indexes are automatically maintained and used by ORACLE. Changes to table data are automatically incorporated into all relevant indexes.
23. What are Clusters ?
Clusters are groups of one or more tables physically stores together to share common columns and are often used together.
24. What is cluster Key ?
The related columns of the tables in a cluster is called the Cluster Key.
25. What is Index Cluster ?
A Cluster with an index on the Cluster Key.
26. What is Hash Cluster ?
A row is stored in a hash cluster based on the result of applying a hash function to the row's cluster key value. All rows with the same hash key value are stores together on disk.
27. When can Hash Cluster used ?
Hash clusters are better choice when a table is often queried with equality queries. For such queries the specified cluster key value is hashed. The resulting hash key value points directly to the area on disk that stores the specified rows.
28. What is Database Link ?
A database link is a named object that describes a "path" from one database to another.
29. What are the types of Database Links ?
Private Database Link, Public Database Link & Network Database Link.
30. What is Private Database Link ?
Private database link is created on behalf of a specific user. A private database link can be used only when the owner of the link specifies a global object name in a SQL statement or in the definition of the owner's views or procedures.
31. What is Public Database Link ?
Public database link is created for the special user group PUBLIC. A public database link can be used when any user in the associated database specifies a global object name in a SQL statement or object definition.
32. What is Network Database link ?
Network database link is created and managed by a network domain service. A network database link can be used when any user of any database in the network specifies a global object name in a SQL statement or object definition.
33. What is Data Block ?
ORACLE database's data is stored in data blocks. One data block corresponds to a specific number of bytes of physical database space on disk.
34. How to define Data Block size ?
A data block size is specified for each ORACLE database when the database is created. A database users and allocated free database space in ORACLE datablocks. Block size is specified in INIT.ORA file and cann't be changed latter.
35. What is Row Chaining ?
In Circumstances, all of the data for a row in a table may not be able to fit in the same data block. When this occurs , the data for the row is stored in a chain of data block (one or more) reserved for that segment.
36. What is an Extent ?
An Extent is a specific number of contiguous data blocks, obtained in a single allocation, used to store a specific type of information.
37. What is a Segment ?
A segment is a set of extents allocated for a certain logical structure.
38. What are the different type of Segments ?
Data Segment, Index Segment, Rollback Segment and Temporary Segment.
39. What is a Data Segment ?
Each Non-clustered table has a data segment. All of the table's data is stored in the extents of its data segment. Each cluster has a data segment. The data of every table in the cluster is stored in the cluster's data segment.
40. What is an Index Segment ?
Each Index has an Index segment that stores all of its data.
41. What is Rollback Segment ?
A Database contains one or more Rollback Segments to temporarily store "undo" information.
42. What are the uses of Rollback Segment ?
Rollback Segments are used :To generate read-consistent database information during database recovery to rollback uncommitted transactions for users.
43. What is a Temporary Segment ?
Temporary segments are created by ORACLE when a SQL statement needs a temporary work area to complete execution. When the statement finishes execution, the temporary segment extents are released to the system for future use.
44. What is a Data File ?
Every ORACLE database has one or more physical data files. A database's data files contain all the database data. The data of logical database structures such as tables and indexes is physically stored in the data files allocated for a database.
45. What are the Characteristics of Data Files ?
A data file can be associated with only one database.Once created a data file can't change size.One or more data files form a logical unit of database storage called a tablespace.
46. What is a Redo Log ?
The set of Redo Log files for a database is collectively known as the database's redo log.
47. What is the function of Redo Log ?
The Primary function of the redo log is to record all changes made to data.
48. What is the use of Redo Log Information ?
The Information in a redo log file is used only to recover the database from a system or media failure prevents database data from being written to a database's data files.
49. What does a Control file Contain ?
A Control file records the physical structure of the database. It contains the following information.
Database NameNames and locations of a database's files and redolog files.Time stamp of database creation.
50. What is the use of Control File ?
When an instance of an ORACLE database is started, its control file is used to identify the database and redo log files that must be opened for database operation to proceed. It is also used in database recovery.
51. What is a Data Dictionary ?
The data dictionary of an ORACLE database is a set of tables and views that are used as a read-only reference about the database.It stores information about both the logical and physical structure of the database, the valid users of an ORACLE database, integrity constraints defined for tables in the database and space allocated for a schema object and how much of it is being used.
52. What is an Integrity Constrains ?
An integrity constraint is a declarative way to define a business rule for a column of a table.
53. Can an Integrity Constraint be enforced on a table if some existing table data does not satisfy the constraint ?No.
54. Describe the different type of Integrity Constraints supported by ORACLE ? NOT NULL Constraint - Disallows NULLs in a table's column.UNIQUE Constraint - Disallows duplicate values in a column or set of columns.PRIMARY KEY Constraint - Disallows duplicate values and NULLs in a column or set of columns.FOREIGN KEY Constrain - Require each value in a column or set of columns match a value in a related table's UNIQUE or PRIMARY KEY.CHECK Constraint - Disallows values that do not satisfy the logical expression of the constraint.
55. What is difference between UNIQUE constraint and PRIMARY KEY constraint ?A column defined as UNIQUE can contain NULLs while a column defined as PRIMARY KEY can't contain Nulls.
56. Describe Referential Integrity ?
A rule defined on a column (or set of columns) in one table that allows the insert or update of a row only if the value for the column or set of columns (the dependent value) matches a value in a column of a related table (the referenced value). It also specifies the type of data manipulation allowed on referenced data and the action to be performed on dependent data as a result of any action on referenced data.
57. What are the Referential actions supported by FOREIGN KEY integrity constraint ?
UPDATE and DELETE Restrict - A referential integrity rule that disallows the update or deletion of referenced data.
DELETE Cascade - When a referenced row is deleted all associated dependent rows are deleted.
58. What is self-referential integrity constraint ?If a foreign key reference a parent key of the same table is called self-referential integrity constraint.
59. What are the Limitations of a CHECK Constraint ?
The condition must be a Boolean expression evaluated using the values in the row being inserted or updated and can't contain subqueries, sequence, the SYSDATE,UID,USER or USERENV SQL functions, or the pseudo columns LEVEL or ROWNUM.
60. What is the maximum number of CHECK constraints that can be defined on a column ?No Limit.
SYSTEM ARCHITECTURE :
61. What constitute an ORACLE Instance ?SGA and ORACLE background processes constitute an ORACLE instance. (or) Combination of memory structure and background process.
62. What is SGA ?The System Global Area (SGA) is a shared memory region allocated by ORACLE that contains data and control information for one ORACLE instance.
63. What are the components of SGA ?Database buffers, Redo Log Buffer the Shared Pool and Cursors.
64. What do Database Buffers contain ?
Database buffers store the most recently used blocks of database data. It can also contain modified data that has not yet been permanently written to disk.
65. What do Redo Log Buffers contain ?Redo Log Buffer stores redo entries a log of changes made to the database.
66. What is Shared Pool ?Shared Pool is a portion of the SGA that contains shared memory constructs such as shared SQL areas.
67. What is Shared SQL Area ?A Shared SQL area is required to process every unique SQL statement submitted to a database and contains information such as the parse tree and execution plan for the corresponding statement.
68. What is Cursor ?A Cursor is a handle ( a name or pointer) for the memory associated with a specific statement.
69. What is PGA ?Program Global Area (PGA) is a memory buffer that contains data and control information for a server process.
70. What is User Process ?A user process is created and maintained to execute the software code of an application program. It is a shadow process created automatically to facilitate communication between the user and the server process.
71. What is Server Process ?Server Process handle requests from connected user process. A server process is in charge of communicating with the user process and interacting with ORACLE carry out requests of the associated user process.
72. What are the two types of Server Configurations ?Dedicated Server Configuration and Multi-threaded Server Configuration.
73. What is Dedicated Server Configuration ?In a Dedicated Server Configuration a Server Process handles requests for a Single User Process.
74. What is a Multi-threaded Server Configuration ?In a Multi-threaded Server Configuration many user processes share a group of server process.
75. What is a Parallel Server option in ORACLE ?A configuration for loosely coupled systems where multiple instance share a single physical database is called Parallel Server.
76. Name the ORACLE Background Process ?DBWR - Database Writer.LGWR - Log WriterCKPT - Check PointSMON - System MonitorPMON - Process MonitorARCH - ArchiverRECO - RecoverDnnn - Dispatcher, andLCKn - LockSnnn - Server.
77. What Does DBWR do ?Database writer writes modified blocks from the database buffer cache to the data files.
78.When Does DBWR write to the database ?DBWR writes when more data needs to be read into the SGA and too few database buffers are free. The least recently used data is written to the data files first. DBWR also writes when CheckPoint occurs.
79. What does LGWR do ?Log Writer (LGWR) writes redo log entries generated in the redo log buffer of the SGA to on-line Redo Log File.
80. When does LGWR write to the database ?LGWR writes redo log entries into an on-line redo log file when transactions commit and the log buffer files are full.
81. What is the function of checkpoint(CKPT)?The Checkpoint (CKPT) process is responsible for signaling DBWR at checkpoints and updating all the data files and control files of the database.
82. What are the functions of SMON ?System Monitor (SMON) performs instance recovery at instance start-up. In a multiple instance system (one that uses the Parallel Server), SMON of one instance can also perform instance recovery for other instance that have failed SMON also cleans up temporary segments that are no longer in use and recovers dead transactions skipped during crash and instance recovery because of file-read or off-line errors. These transactions are eventually recovered by SMON when the tablespace or file is brought back on-line SMON also coalesces free extents within the database to make free space contiguous and easier to allocate.
83. What are functions of PMON ?Process Monitor (PMON) performs process recovery when a user process fails PMON is responsible for cleaning up the cache and Freeing resources that the process was using PMON also checks on dispatcher and server processes and restarts them if they have failed.
84. What is the function of ARCH ?Archiver (ARCH) copies the on-line redo log files to archival storage when they are full. ARCH is active only when a database's redo log is used in ARCHIVELOG mode.
85. What is function of RECO ?RECOver (RECO) is used to resolve distributed transactions that are pending due to a network or system failure in a distributed database. At timed intervals,the local RECO attempts to connect to remote databases and automatically complete the commit or rollback of the local portion of any pending distributed transactions.
86. What is the function of Dispatcher (Dnnn) ?Dispatcher (Dnnn) process is responsible for routing requests from connected user processes to available shared server processes and returning the responses back to the appropriate user processes.
87. How many Dispatcher Processes are created ?Atleast one Dispatcher process is created for every communication protocol in use.
88. What is the function of Lock (LCKn) Process ?Lock (LCKn) are used for inter-instance locking when the ORACLE Parallel Server option is used.
89. What is the maximum number of Lock Processes used ?Though a single LCK process is sufficient for most Parallel Server systemsupto Ten Locks (LCK0,....LCK9) are used for inter-instance locking.
DATA ACCESS
90. Define Transaction ?A Transaction is a logical unit of work that comprises one or more SQL statements executed by a single user.
91. When does a Transaction end ?When it is committed or Rollbacked.
92. What does COMMIT do ?COMMIT makes permanent the changes resulting from all SQL statements in the transaction. The changes made by the SQL statements of a transaction become visible to other user sessions transactions that start only after transaction is committed.
93. What does ROLLBACK do ?ROLLBACK retracts any of the changes resulting from the SQL statements in the transaction.
94. What is SAVE POINT ?For long transactions that contain many SQL statements, intermediate markers or savepoints can be declared which can be used to divide a transaction into smaller parts. This allows the option of later rolling back all work performed from the current point in the transaction to a declared savepoint within the transaction.
95. What is Read-Only Transaction ?A Read-Only transaction ensures that the results of each query executed in the transaction are consistant with respect to the same point in time.
96. What is the function of Optimizer ?
The goal of the optimizer is to choose the most efficient way to execute a SQL statement.
97. What is Execution Plan ?The combinations of the steps the optimizer chooses to execute a statement is called an execution plan.
98. What are the different approaches used by Optimizer in choosing an execution plan ?Rule-based and Cost-based.
99. What are the factors that affect OPTIMIZER in choosing an Optimization approach ?The OPTIMIZER_MODE initialization parameter Statistics in the Data Dictionary the OPTIMIZER_GOAL parameter of the ALTER SESSION command hints in the statement.
100. What are the values that can be specified for OPTIMIZER MODE Parameter ?COST and RULE.
101. Will the Optimizer always use COST-based approach if OPTIMIZER_MODE is set to "Cost'?
Presence of statistics in the data dictionary for atleast one of the tables accessed by the SQL statements is necessary for the OPTIMIZER to use COST-based approach. Otherwise OPTIMIZER chooses RULE-based approach.
102. What is the effect of setting the value of OPTIMIZER_MODE to 'RULE' ?
This value causes the optimizer to choose the rule_based approach for all SQL statements issued to the instance regardless of the presence of statistics.
103. What are the values that can be specified for OPTIMIZER_GOAL parameter of the ALTER SESSION Command ?
CHOOSE,ALL_ROWS,FIRST_ROWS and RULE.
104. What is the effect of setting the value "CHOOSE" for OPTIMIZER_GOAL, parameter of the ALTER SESSION Command ?The Optimizer chooses Cost_based approach and optimizes with the goal of best throughput if statistics for atleast one of the tables accessed by the SQL statement exist in the data dictionary. Otherwise the OPTIMIZER chooses RULE_based approach.
105. What is the effect of setting the value "ALL_ROWS" for OPTIMIZER_GOAL parameter of the ALTER SESSION command ?This value causes the optimizer to the cost-based approach for all SQL statements in the session regardless of the presence of statistics and to optimize with a goal of best throughput.
106. What is the effect of setting the value 'FIRST_ROWS' for OPTIMIZER_GOAL parameter of the ALTER SESSION command ?This value causes the optimizer to use the cost-based approach for all SQL statements in the session regardless of the presence of statistics and to optimize with a goal of best response time.
107. What is the effect of setting the 'RULE' for OPTIMIER_GOAL parameter of the ALTER SESSION Command ?This value causes the optimizer to choose the rule-based approach for all SQL statements in a session regardless of the presence of statistics.
108. What is RULE-based approach to optimization ?Choosing an executing planbased on the access paths available and the ranks of these access paths.
109. What is COST-based approach to optimization ?Considering available access paths and determining the most efficient execution plan based on statistics in the data dictionary for the tables accessed by the statement and their associated clusters and indexes.
PROGRAMMATIC CONSTRUCTS
110. What are the different types of PL/SQL program units that can be defined and stored in ORACLE database ?
Procedures and Functions,Packages and Database Triggers.
111. What is a Procedure ?A Procedure consist of a set of SQL and PL/SQL statements that are grouped together as a unit to solve a specific problem or perform a set of related tasks.
112. What is difference between Procedures and Functions ?A Function returns a value to the caller where as a Procedure does not.
113. What is a Package ?A Package is a collection of related procedures, functions, variables and other package constructs together as a unit in the database.
114. What are the advantages of having a Package ?Increased functionality (for example,global package variables can be declared and used by any proecdure in the package) and performance (for example all objects of the package are parsed compiled, and loaded into memory once)
115. What is Database Trigger ?A Database Trigger is procedure (set of SQL and PL/SQL statements) that is automatically executed as a result of an insert in,update to, or delete from a table.
116. What are the uses of Database Trigger ?Database triggers can be used to automatic data generation, audit data modifications, enforce complex Integrity constraints, and customize complex security authorizations.
117. What are the differences between Database Trigger and Integrity constraints ?A declarative integrity constraint is a statement about the database that is always true. A constraint applies to existing data in the table and any statement that manipulates the table.
A trigger does not apply to data loaded before the definition of the trigger, therefore, it does not guarantee all data in a table conforms to the rules established by an associated trigger.
A trigger can be used to enforce transitional constraints where as a declarative integrity constraint cannot be used.
DATABASE SECURITY
118. What are Roles ?Roles are named groups of related privileges that are granted to users or other roles.
119. What are the use of Roles ?REDUCED GRANTING OF PRIVILEGES - Rather than explicitly granting the same set of privileges to many users a database administrator can grant the privileges for a group of related users granted to a role and then grant only the role to each member of the group.
DYNAMIC PRIVILEGE MANAGEMENT - When the privileges of a group must change, only the privileges of the role need to be modified. The security domains of all users granted the group's role automatically reflect the changes made to the role.
SELECTIVE AVAILABILITY OF PRIVILEGES - The roles granted to a user can be selectively enable (available for use) or disabled (not available for use). This allows specific control of a user's privileges in any given situation.
APPLICATION AWARENESS - A database application can be designed to automatically enable and disable selective roles when a user attempts to use the application.
120. How to prevent unauthorized use of privileges granted to a Role ?By creating a Role with a password.
121. What is default tablespace ?The Tablespace to contain schema objects created without specifying a tablespace name.
122. What is Tablespace Quota ?The collective amount of disk space available to the objects in a schema on a particular tablespace.
123. What is a profile ?Each database user is assigned a Profile that specifies limitations on various system resources available to the user.
124. What are the system resources that can be controlled through Profile ?The number of concurrent sessions the user can establish the CPU processing time available to the user's session the CPU processing time available to a single call to ORACLE made by a SQL statement the amount of logical I/O available to the user's session the amout of logical I/O available to a single call to ORACLE made by a SQL statement the allowed amount of idle time for the user's session the allowed amount of connect time for the user's session.
125. What is Auditing ?Monitoring of user access to aid in the investigation of database use.
126. What are the different Levels of Auditing ?Statement Auditing, Privilege Auditing and Object Auditing.
127. What is Statement Auditing ?Statement auditing is the auditing of the powerful system privileges without regard to specifically named objects.
128. What is Privilege Auditing ?Privilege auditing is the auditing of the use of powerful system privileges without regard to specifically named objects.
129. What is Object Auditing ?Object auditing is the auditing of accesses to specific schema objects without regard to user.
DISTRIBUTED PROCESSING AND DISTRIBUTED DATABASES
130. What is Distributed database ?A distributed database is a network of databases managed by multiple database servers that appears to a user as single logical database. The data of all databases in the distributed database can be simultaneously accessed and modified.
131. What is Two-Phase Commit ?Two-phase commit is mechanism that guarantees a distributed transaction either commits on all involved nodes or rolls back on all involved nodes to maintain data consistency across the global distributed database. It has two phase, a Prepare Phase and a Commit Phase.
132. Describe two phases of Two-phase commit ?Prepare phase - The global coordinator (initiating node) ask a participants to prepare (to promise to commit or rollback the transaction, even if there is a failure)
Commit - Phase - If all participants respond to the coordinator that they are prepared, the coordinator asks all nodes to commit the transaction, if all participants cannot prepare, the coordinator asks all nodes to roll back the transaction.
133. What is the mechanism provided by ORACLE for table replication ?Snapshots and SNAPSHOT LOGs
134. What is a SNAPSHOT ?Snapshots are read-only copies of a master table located on a remote node which is periodically refreshed to reflect changes made to the master table.
135. What is a SNAPSHOT LOG ?A snapshot log is a table in the master database that is associated with the master table. ORACLE uses a snapshot log to track the rows that have been updated in the master table. Snapshot logs are used in updating the snapshots based on the master table.
136. What is a SQL * NET?SQL *NET is ORACLE's mechanism for interfacing with the communication protocols used by the networks that facilitate distributed processing and distributed databases. It is used in Clint-Server and Server-Server communications.
DATABASE OPERATION, BACKUP AND RECOVERY
137. What are the steps involved in Database Startup ?Start an instance, Mount the Database and Open the Database.
138. What are the steps involved in Database Shutdown ?Close the Database, Dismount the Database and Shutdown the Instance.
139. What is Restricted Mode of Instance Startup ?An instance can be started in (or later altered to be in) restricted mode so that when the database is open connections are limited only to those whose user accounts have been granted the RESTRICTED SESSION system privilege.
140. What are the different modes of mounting a Database with the Parallel Server ?
Exclusive Mode If the first instance that mounts a database does so in exclusive mode, only that Instance can mount the database.
Parallel Mode If the first instance that mounts a database is started in parallel mode, other instances that are started in parallel mode can also mount the database.
141. What is Full Backup ?A full backup is an operating system backup of all data files, on-line redo log files and control file that constitute ORACLE database and the parameter.
142. Can Full Backup be performed when the database is open ?No.
143. What is Partial Backup ?A Partial Backup is any operating system backup short of a full backup, taken while the database is open or shut down.
144.WhatisOn-lineRedoLog?The On-line Redo Log is a set of tow or more on-line redo files that record all committed changes made to the database. Whenever a transaction is committed, the corresponding redo entries temporarily stores in redo log buffers of the SGA are written to an on-line redo log file by the background process LGWR. The on-line redo log files are used in cyclical fashion.
145. What is Mirrored on-line Redo Log ?A mirrored on-line redo log consists of copies of on-line redo log files physically located on separate disks, changes made to one member of the group are made to all members.
146. What is Archived Redo Log ?Archived Redo Log consists of Redo Log files that have archived before being reused.
147. What are the advantages of operating a database in ARCHIVELOG mode over operating it in NO ARCHIVELOG mode ?Complete database recovery from disk failure is possible only in ARCHIVELOG mode.Online database backup is possible only in ARCHIVELOG mode.
148. What is Log Switch ?The point at which ORACLE ends writing to one online redo log file and begins writing to another is called a log switch.
149. What are the steps involved in Instance Recovery ?R_olling forward to recover data that has not been recorded in data files, yet has been recorded in the on-line redo log, including the contents of rollback segments.
Rolling back transactions that have been explicitly rolled back or have not been committed as indicated by the rollback segments regenerated in step a. Releasing any resources (locks) held by transactions in process at the time of the failure.
Resolving any pending distributed transactions undergoing a two-phase commit at the time of the instance failure.
Data Base Administration
Introduction to DBA
1. What is a Database instance ? Explain
A database instance (Server) is a set of memory structure and background processes that access a set of database files.
The process can be shared by all users.
The memory structure that are used to store most queried data from database. This helps up to improve database performance by decreasing the amount of I/O performed against data file.
2. What is Parallel Server ?
Multiple instances accessing the same database (Only In Multi-CPU environments)
3. What is a Schema ?
The set of objects owned by user account is called the schema.
4. What is an Index ? How it is implemented in Oracle Database ?
An index is a database structure used by the server to have direct access of a row in a table.
An index is automatically created when a unique of primary key constraint clause is specified in create table comman (Ver 7.0)
5. What is clusters ?
Group of tables physically stored together because they share common columns and are often used together is called Cluster.
6. What is a cluster Key ?
The related columns of the tables are called the cluster key. The cluster key is indexed using a cluster index and its value is stored only once for multiple tables in the cluster.
7. What are the basic element of Base configuration of an oracle Database ?
It consists ofone or more data files.one or more control files.two or more redo log files.The Database containsmultiple users/schemasone or more rollback segmentsone or more tablespacesData dictionary tablesUser objects (table,indexes,views etc.,)The server that access the database consists ofSGA (Database buffer, Dictionary Cache Buffers, Redo log buffers, Shared SQL pool)SMON (System MONito)PMON (Process MONitor)LGWR (LoG Write)DBWR (Data Base Write)ARCH (ARCHiver)CKPT (Check Point)RECODispatcherUser Process with associated PGS
8. What is a deadlock ? Explain .
Two processes wating to update the rows of a table which are locked by the other process then deadlock arises.
In a database environment this will often happen because of not issuing proper row lock commands. Poor design of front-end application may cause this situation and the performance of server will reduce drastically.
These locks will be released automatically when a commit/rollback operation performed or any one of this processes being killed externally.
MEMORY MANAGEMENT
9. What is SGA ? How it is different from Ver 6.0 and Ver 7.0 ?
The System Global Area in a Oracle database is the area in memory to facilitates the transfer of information between users. It holds the most recently requested structural information between users. It holds the most recently requested structural information about the database.
The structure is Database buffers, Dictionary cache, Redo Log Buffer and Shared SQL pool (ver 7.0 only) area.
10. What is a Shared SQL pool ?
The data dictionary cache is stored in an area in SGA called the Shared SQL Pool. This will allow sharing of parsed SQL statements among concurrent users.
11. What is mean by Program Global Area (PGA) ?
It is area in memory that is used by a Single Oracle User Process.
12. What is a data segment ?
Data segment are the physical areas within a database block in which the data associated with tables and clusters are stored.
13. What are the factors causing the reparsing of SQL statements in SGA?
Due to insufficient Shared SQL pool size.
Monitor the ratio of the reloads takes place while executing SQL statements. If the ratio is greater than 1 then increase the SHARED_POOL_SIZE.
LOGICAL & PHYSICAL ARCHITECTURE OF DATABASE.
14. What is Database Buffers ?
Database buffers are cache in the SGA used to hold the data blocks that are read from the data segments in the database such as tables, indexes and clusters DB_BLOCK_BUFFERS parameter in INIT.ORA decides the size.
15. What is dictionary cache ?
Dictionary cache is information about the databse objects stored in a data dictionary table.
16. What is meant by recursive hints ?
Number of times processes repeatedly query the dictionary table is called recursive hints. It is due to the data dictionary cache is too small. By increasing the SHARED_POOL_SIZE parameter we can optimize the size of Data Dictionary Cache.
17. What is meant by redo log buffer ?
Change made to entries are written to the on-line redo log files. So that they can be used in roll forward operations during database recoveries. Before writing them into the redo log files, they will first brought to redo log buffers in SGA and LGWR will write into files frequently.LOG_BUFFER parameter will decide the size.
18. How will you swap objects into a different table space for an existing database ?
Export the user
Perform import using the command imp system/manager file=export.dmp indexfile=newrite.sql. This will create all definitions into newfile.sql.
Drop necessary objects.
Run the script newfile.sql after altering the tablespaces.
Import from the backup for the necessary objects.
19. List the Optional Flexible Architecture (OFA) of Oracle database ? or How can we organise the tablespaces in Oracle database to have maximum performance ?
SYSTEM - Data dictionary tables.DATA - Standard operational tables.DATA2- Static tables used for standard operationsINDEXES - Indexes for Standard operational tables.INDEXES1 - Indexes of static tables used for standard operations.TOOLS - Tools table.TOOLS1 - Indexes for tools table.RBS - Standard Operations Rollback Segments,RBS1,RBS2 - Additional/Special Rollback segments.TEMP - Temporary purpose tablespaceTEMP_USER - Temporary tablespace for users.USERS - User tablespace.
20. How will you force database to use particular rollback segment ?
SET TRANSACTION USE ROLLBACK SEGMENT rbs_name.
21. What is meant by free extent ?
A free extent is a collection of continuous free blocks in tablespace. When a segment is dropped its extents are reallocated and are marked as free.
22. How free extents are managed in Ver 6.0 and Ver 7.0 ?
Free extents cannot be merged together in Ver 6.0.Free extents are periodically coalesces with the neighboring free extent inVer 7.0
23.Which parameter in Storage clause will reduce no. of rows per block?
PCTFREE parameter
Row size also reduces no of rows per block.
24. What is the significance of having storage clause ?
We can plan the storage for a table as how much initial extents are required, how much can be extended next, how much % should leave free for managing row updations etc.,
25. How does Space allocation table place within a block ?
Each block contains entries as followsFixied block headerVariable block headerRow Header,row date (multiple rows may exists)PCTEREE (% of free space for row updation in future)
26. What is the role of PCTFREE parameter is Storage clause ?
This is used to reserve certain amount of space in a block for expansion of rows.
27. What is the OPTIMAL parameter ?
It is used to set the optimal length of a rollback segment.
28. What is the functionality of SYSTEM table space ?
To manage the database level transactions such as modifications of the data dictionary table that record information about the free space usage.
29. How will you create multiple rollback segments in a database ?
Create a database which implicitly creates a SYSTEM Rollback Segment in a SYSTEM tablespace.
Create a Second Rollback Segment name R0 in the SYSTEM tablespace.
Make new rollback segment available (After shutdown, modify init.ora file and Start database)
Create other tablespaces (RBS) for rollback segments.
Deactivate Rollback Segment R0 and activate the newly created rollback segments.
30. How the space utilisation takes place within rollback segments ?
It will try to fit the transaction in a cyclic fashion to all existing extents. Once it found an extent is in use then it forced to acquire a new extent (No. of extents is based on the optimal size)
31. Why query fails sometimes ?
Rollback segment dynamically extent to handle larger transactions entry loads.
A single transaction may wipeout all avaliable free space in the Rollback Segment Tablespace. This prevents other user using Rollback segments.
32. How will you monitor the space allocation ?
By quering DBA_SEGMENT table/view.
33. How will you monitor rollback segment status ?
Querying the DBA_ROLLBACK_SEGS viewIN USE - Rollback Segment is on-line.AVAILABLE - Rollback Segment available but not on-line.OFF-LINE - Rollback Segment off-lineINVALID - Rollback Segment Dropped.NEEDS RECOVERY - Contains data but need recovery or corupted.PARTLY AVAILABLE - Contains data from an unresolved transaction involving a distributed database.
34. List the sequence of events when a large transaction that exceeds beyond its optimal value when an entry wraps and causes the rollback segment to expand into another extend.
Transaction Begins.
An entry is made in the RES header for new transactions entry
Transaction acquires blocks in an extent of RBS
The entry attempts to wrap into second extent. None is available, so that the RBS must extent.
The RBS checks to see if it is part of its OPTIMAL size.RBS chooses its oldest inactive segment.Oldest inactive segment is eliminated.RBS extentsThe Data dictionary table for space management are updated.Transaction Completes.
35. How can we plan storage for very large tables ?
Limit the number of extents in the tableSeparate Table from its indexes.Allocate Sufficient temporary storage.
36. How will you estimate the space required by a non-clustered tables?
Calculate the total header sizeCalculate the available dataspace per data blockCalculate the combined column lengths of the average rowCalculate the total average row size.Calculate the average number rows that can fit in a blockCalculate the number of blocks and bytes required for the table.
After arriving the calculation, add 10 % additional space to calculate the initial extent size for a working table.
37. It is possible to use raw devices as data files and what is the advantages over file. system files ?
Yes.
The advantages over file system files.
I/O will be improved because Oracle is bye-passing the kernnel which writing into disk.Disk Corruption will be very less.
38. What is a Control file ?
Database's overall physical architecture is maintained in a file called control file. It will be used to maintain internal consistency and guide recovery operations. Multiple copies of control files are advisable.
39. How to implement the multiple control files for an existing database ?
Shutdown the databseCopy one of the existing control file to new locationEdit Config ora file by adding new control file.nameRestart the database.
40. What is meant by Redo Log file mirrorring ? How it can be achieved?
Process of having a copy of redo log files is called mirroring.
This can be achieved by creating group of log files together, so that LGWR will automatically writes them to all the members of the current on-line redo log group. If any one group fails then database automatically switch over to next group. It degrades performance.
41. What is advantage of having disk shadowing/ Mirroring ?
Shadow set of disks save as a backup in the event of disk failure. In most Operating System if any disk failure occurs it automatically switchover to place of failed disk.
Improved performance because most OS support volume shadowing can direct file I/O request to use the shadow set of files instead of the main set of files. This reduces I/O load on the main set of disks.
42. What is use of Rollback Segments In Database ?
They allow the database to maintain read consistency between multiple transactions.
43. What is a Rollback segment entry ?
It is the set of before image data blocks that contain rows that are modified by a transaction.Each Rollback Segment entry must be completed within one rollback segment.
A single rollback segment can have multiple rollback segment entries.
44. What is hit ratio ?
It is a measure of well the data cache buffer is handling requests for data.
Hit Ratio = (Logical Reads - Physical Reads - Hits Misses)/ Logical Reads.
45. When will be a segment released ?
When Segment is dropped.When Shrink (RBS only)When truncated (TRUNCATE used with drop storage option)
46. What are disadvanteges of having raw devices ?
We should depend on export/import utility for backup/recovery (fully reliable)
The tar command cannot be used for physical file backup, instead we can use dd command which is less flexible and has limited recoveries.
47. List the factors that can affect the accuracy of the estimations ?
The space used transaction entries and deleted records does not become free immediately after completion due to delayed cleanout.
Trailling nulls and length bytes are not stored.
Inserts of, updates to and deletes of rows as well as columns larger than a single datablock, can cause fragmentation an chained row pieces.
DATABASE SECURITY & ADMINISTRATION
48. What is user Account in Oracle database ?
An user account is not a physical structure in Database but it is having important relationship to the objects in the database and will be having certain privileges.
49. How will you enforce security using stored procedures ?
Don't grant user access directly to tables within the application.
Instead grant the ability to access the procedures that access the tables.
When procedure executed it will execute the privilege of procedures owner. Users cannot access tables except via the procedure.
50. What are the dictionary tables used to monitor a database spaces ?
DBA_FREE_SPACEDBA_SEGMENTSDBA_DATA_FILES.
51. What are the responsibilities of a Database Administrator ?
Installing and upgrading the Oracle Server and application tools.Allocating system storage and planning future storage requirements for the database system.Managing primary database structures (tablespaces)Managing primary objects (table,views,indexes)Enrolling users and maintaining system security.Ensuring compliance with Oralce license agreementControlling and monitoring user access to the database.Monitoring and optimising the performance of the database.Planning for backup and recovery of database information.Maintain archived data on tapeBacking up and restoring the database.Contacting Oracle Corporation for technical support.
52. What are the roles and user accounts created automatically with the database ?
DBA - role Contains all database system privileges.
SYS user account - The DBA role will be assigned to this account. All of the basetables and views for the database's dictionary are store in this schema and are manipulated only by ORACLE.
SYSTEM user account - It has all the system privileges for the database and additional tables and views that display administrative information and internal tables and views used by oracle tools are created using this username.
54. What are the database administrators utilities avaliable ?
SQL * DBA - This allows DBA to monitor and control an ORACLE database.
SQL * Loader - It loads data from standard operating system files (Flat files) into ORACLE database tables.
Export (EXP) and Import (imp) utilities allow you to move existing data in ORACLE format to and from ORACLE database.
55. What are the minimum parameters should exist in the parameter file (init.ora) ?
DB NAME - Must set to a text string of no more than 8 characters and it will be stored inside the datafiles, redo log files and control files and control file while database creation.
DB_DOMAIN - It is string that specifies the network domain where the database is created. The global database name is identified by setting these parameters (DB_NAME & DB_DOMAIN)
CONTORL FILES - List of control filenames of the database. If name is not mentioned then default name will be used.
DB_BLOCK_BUFFERS - To determine the no of buffers in the buffer cache in SGA.
PROCESSES - To determine number of operating system processes that can be connected to ORACLE concurrently. The value should be 5 (background process) and additional 1 for each user.
ROLLBACK_SEGMENTS - List of rollback segments an ORACLE instance acquires at database startup.
Also optionally LICENSE_MAX_SESSIONS,LICENSE_SESSION_WARNING and LICENSE_MAX_USERS.
56. What is a trace file and how is it created ?
Each server and background process can write an associated trace file. When an internal error is detected by a process or user process, it dumps information about the error to its trace. This can be used for tuning the database.
57. What are roles ? How can we implement roles ?
Roles are the easiest way to grant and manage common privileges needed by different groups of database users.
Creating roles and assigning provies to roles.
Assign each role to group of users. This will simplify the job of assigning privileges to individual users.
58. What are the steps to switch a database's archiving mode between NO ARCHIVELOG and ARCHIVELOG mode ?
1. Shutdown the database instance.2. Backup the databse3. Perform any operating system specific steps (optional)4. Start up a new instance and mount but do not open the databse.5. Switch the databse's archiving mode.
59. How can you enable automatic archiving ?
Shut the databaseBackup the databaseModify/Include LOG_ARCHIVE_START_TRUE in init.ora file.Start up the databse.
60. How can we specify the Archived log file name format and destination ?
By setting the following values in init.ora file.
LOG_ARCHIVE_FORMAT = arch %S/s/T/tarc (%S - Log sequence number and is zero left paded, %s - Log sequence number not padded. %T - Thread number lef-zero-paded and %t - Thread number not padded). The file name created is arch 0001 are if %S is used.LOG_ARCHIVE_DEST = path.
61. What is the use of ANALYZE command ?
To perform one of these function on an index,table, or cluster:
- to collect statisties about object used by the optimizer and store them in the data dictionary.- to delete statistics about the object used by object from the data dictionary.- to validate the structure of the object.- to identify migrated and chained rows of the table or cluster.
MANAGING DISTRIBUTED DATABASES.
62. How can we reduce the network traffic ?- Replictaion of data in distributed environment.- Using snapshots to replicate data.- Using remote procedure calls.
63. What is snapshots ?
Snapshot is an object used to dynamically replicate data between distribute database at specified time intervals. In ver 7.0 they are read only.
64. What are the various type of snapshots ?
Simple and Complex.
65. Differentiate simple and complex, snapshots ?
- A simple snapshot is based on a query that does not contains GROUP BY clauses, CONNECT BY clauses, JOINs, sub-query or snashot of operations.- A complex snapshots contain atleast any one of the above.
66. What dynamic data replication ?
Updating or Inserting records in remote database through database triggers. It may fail if remote database is having any problem.
67. How can you Enforce Refrencial Integrity in snapshots ?
Time the references to occur when master tables are not in use.Peform the reference the manually immdiately locking the master tables. We can join tables in snopshots by creating a complex snapshots that will based on the master tables.
68. What are the options available to refresh snapshots ?
COMPLETE - Tables are completly regenerated using the snapshot's query and the master tables every time the snapshot referenced.FAST - If simple snapshot used then a snapshot log can be used to send the changes to the snapshot tables.FORCE - Default value. If possible it performs a FAST refresh; Otherwise it will perform a complete refresh.
69. what is snapshot log ?
It is a table that maintains a record of modifications to the master table in a snapshot. It is stored in the same database as master table and is only available for simple snapshots. It should be created before creating snapshots.
70. When will the data in the snapshot log be used ?
We must be able to create a after row trigger on table (i.e., it should be not be already available )
After giving table privileges.
We cannot specify snapshot log name because oracle uses the name of the master table in the name of the database objects that support its snapshot log.
The master table name should be less than or equal to 23 characters.
(The table name created will be MLOGS_tablename, and trigger name will be TLOGS name).
72. What are the benefits of distributed options in databases ?
Database on other servers can be updated and those transactions can be grouped together with others in a logical unit.Database uses a two phase commit.
MANAGING BACKUP & RECOVERY
73. What are the different methods of backing up oracle database ?
- Logical Backups- Cold Backups- Hot Backups (Archive log)
74. What is a logical backup ?
Logical backup involves reading a set of databse records and writing them into a file. Export utility is used for taking backup and Import utility is used to recover from backup.
75. What is cold backup ? What are the elements of it ?
Cold backup is taking backup of all physical files after normal shutdown of database. We need to take.- All Data files.- All Control files.- All on-line redo log files.- The init.ora file (Optional)
76. What are the different kind of export backups ?
Full back - Complete databaseIncremental - Only affected tables from last incremental date/full backup date.Cumulative backup - Only affected table from the last cumulative date/full backup date.
77. What is hot backup and how it can be taken ?
Taking backup of archive log files when database is open. For this the ARCHIVELOG mode should be enabled. The following files need to be backed up. All data files. All Archive log, redo log files. All control files.
78. What is the use of FILE option in EXP command ?
To give the export file name.
79. What is the use of COMPRESS option in EXP command ?
Flag to indicate whether export should compress fragmented segments into single extents.
80. What is the use of GRANT option in EXP command ?
A flag to indicate whether grants on databse objects will be exported or not. Value is 'Y' or 'N'.
81. What is the use of INDEXES option in EXP command ?
A flag to indicate whether indexes on tables will be exported.
82. What is the use of ROWS option in EXP command ?
Flag to indicate whether table rows should be exported. If 'N' only DDL statements for the databse objects will be created.
83. What is the use of CONSTRAINTS option in EXP command ?
A flag to indicate whether constraints on table need to be exported.
84. What is the use of FULL option in EXP command ?
A flag to indicate whether full databse export should be performed.
85. What is the use of OWNER option in EXP command ?List of table accounts should be exported.
86. What is the use of TABLES option in EXP command ?
List of tables should be exported.
87. What is the use of RECORD LENGTH option in EXP command ?
Record length in bytes.
88. What is the use of INCTYPE option in EXP command ?
Type export should be performed COMPLETE,CUMULATIVE,INCREMENTAL.
89. What is the use of RECORD option in EXP command ?
For Incremental exports, the flag indirects whether a record will be stores data dictionary tables recording the export.
90. What is the use of PARFILE option in EXP command ?
Name of the parameter file to be passed for export.
91. What is the use of PARFILE option in EXP command ?
Name of the parameter file to be passed for export.
92. What is the use of ANALYSE ( Ver 7) option in EXP command ?
A flag to indicate whether statistical information about the exported objects should be written to export dump file.
93. What is the use of CONSISTENT (Ver 7) option in EXP command ?
A flag to indicate whether a read consistent version of all the exported objects should be maintained.
94. What is use of LOG (Ver 7) option in EXP command ?
The name of the file which log of the export will be written.
95.What is the use of FILE option in IMP command ?
The name of the file from which import should be performed.
96. What is the use of SHOW option in IMP command ?
A flag to indicate whether file content should be displayed or not.
97. What is the use of IGNORE option in IMP command ?
A flag to indicate whether the import should ignore errors encounter when issuing CREATE commands.
98. What is the use of GRANT option in IMP command ?
A flag to indicate whether grants on database objects will be imported.
99. What is the use of INDEXES option in IMP command ?
A flag to indicate whether import should import index on tables or not.
100. What is the use of ROWS option in IMP command ?
A flag to indicate whether rows should be imported. If this is set to 'N' then only DDL for database objects will be exectued.
SQL PLUS STATEMENTS
1. What are the types of SQL Statement ?
Data Definition Language : CREATE,ALTER,DROP,TRUNCATE,REVOKE,NO AUDIT & COMMIT.Data Manipulation Language : INSERT,UPDATE,DELETE,LOCK TABLE,EXPLAIN PLAN & SELECT.Transactional Control : COMMIT & ROLLBACKSession Control : ALTERSESSION & SET ROLESystem Control : ALTER SYSTEM.
2. What is a transaction ?
Transaction is logical unit between two commits and commit and rollback.
3. What is difference between TRUNCATE & DELETE ?
TRUNCATE commits after deleting entire table i.e., can not be rolled back. Database triggers do not fire on TRUNCATE
DELETE allows the filtered deletion. Deleted records can be rolled back or committed.Database triggers fire on DELETE.
4. What is a join ? Explain the different types of joins ?
Join is a query which retrieves related columns or rows from multiple tables.
Self Join - Joining the table with itself.Equi Join - Joining two tables by equating two common columns.Non-Equi Join - Joining two tables by equating two common columns.Outer Join - Joining two tables in such a way that query can also retrive rows that do not have corresponding join value in the other table.
5. What is the Subquery ?
Subquery is a query whose return values are used in filtering conditions of the main query.
6. What is correlated sub-query ?
Correlated sub_query is a sub_query which has reference to the main query.
7. Explain Connect by Prior ?
Retrives rows in hierarchical order.e.g. select empno, ename from emp where.
8. Difference between SUBSTR and INSTR ?
INSTR (String1,String2(n,(m)),INSTR returns the position of the mth occurrence of the string 2 instring1. The search begins from nth position of string1.
SUBSTR (String1 n,m)SUBSTR returns a character string of size m in string1, starting from nth postion of string1.
9. Explain UNION,MINUS,UNION ALL, INTERSECT ?
INTERSECT returns all distinct rows selected by both queries.MINUS - returns all distinct rows selected by the first query but not by the second.UNION - returns all distinct rows selected by either queryUNION ALL - returns all rows selected by either query,including all duplicates.
10. What is ROWID ?
ROWID is a pseudo column attached to each row of a table. It is 18 character long, blockno, rownumber are the components of ROWID.
11. What is the fastest way of accessing a row in a table ?
Using ROWID.
CONSTRAINTS
12. What is an Integrity Constraint ?
Integrity constraint is a rule that restricts values to a column in a table.
13. What is Referential Integrity ?
Maintaining data integrity through a set of rules that restrict the values of one or more columns of the tables based on the values of primary key or unique key of the referenced table.
14. What are the usage of SAVEPOINTS ?
SAVEPOINTS are used to subdivide a transaction into smaller parts. It enables rolling back part of a transaction. Maximum of five save points are allowed.
15. What is ON DELETE CASCADE ?
When ON DELETE CASCADE is specified ORACLE maintains referential integrity by automatically removing dependent foreign key values if a referenced primary or unique key value is removed.
16. What are the data types allowed in a table ?
CHAR,VARCHAR2,NUMBER,DATE,RAW,LONG and LONG RAW.
17. What is difference between CHAR and VARCHAR2 ? What is the maximum SIZE allowed for each type ?
CHAR pads blank spaces to the maximum length. VARCHAR2 does not pad blank spaces. For CHAR it is 255 and 2000 for VARCHAR2.
18. How many LONG columns are allowed in a table ? Is it possible to use LONG columns in WHERE clause or ORDER BY ?
Only one LONG columns is allowed. It is not possible to use LONG column in WHERE or ORDER BY clause.
19. What are the pre requisites ?I. to modify datatype of a column ?ii. to add a column with NOT NULL constraint ?
To Modify the datatype of a column the column must be empty.to add a column with NOT NULL constrain, the table must be empty.
20. Where the integrity constrints are stored in Data Dictionary ?
The integrity constraints are stored in USER_CONSTRAINTS.
21. How will you a activate/deactivate integrity constraints ?
The integrity constraints can be enabled or disabled by ALTER TABLE ENABLE constraint/DISABLE constraint.
22. If an unique key constraint on DATE column is created, will it validate the rows that are inserted with SYSDATE ?
It won't, Because SYSDATE format contains time attached with it.
23. What is a database link ?
Database Link is a named path through which a remote database can be accessed.
24. How to access the current value and next value from a sequence ? Is it possible to access the current value in a session before accessing next value ?
Sequence name CURRVAL, Sequence name NEXTVAL.
It is not possible. Only if you access next value in the session, current value can be accessed.
25. What is CYCLE/NO CYCLE in a Sequence ?
CYCLE specifies that the sequence continues to generate values after reaching either maximum or minimum value. After pan ascending sequence reaches its maximum value, it generates its minimum value. After a descending sequence reaches its minimum, it generates its maximum.
NO CYCLE specifies that the sequence cannot generate more values after reaching its maximum or minimum value.
26. What are the advantages of VIEW ?
To protect some of the columns of a table from other users.To hide complexity of a query.To hide complexity of calculations.
27. Can a view be updated/inserted/deleted? If Yes under what conditions ?
A View can be updated/deleted/inserted if it has only one base table if the view is based on columns from one or more tables then insert, update and delete is not possible.
28.If a View on a single base table is manipulated will the changes be reflected on the base table ?
If changes are made to the tables which are base tables of a view will the changes be reference on the view.
FORMS 3.0 BASIC
1.What is an SQL *FORMS ?
SQL *forms is 4GL tool for developing and executing; Oracle based interactive application.
2. What is the maximum size of a form ?
255 character width and 255 characters Length.
3. Name the two files that are created when you generate the form give the filex extension ?
INP (Source File)FRM (Executable File)
4. How do you control the constraints in forms ?
Select the use constraint property is ON Block definition screen.
BLOCK
5. Commited block sometimes refer to a BASE TABLE ? True or False.
False.
6. Can we create two blocks with the same name in form 3.0 ?
No.
7. While specifying master/detail relationship between two blocks specifying the join condition is a must ? True or False.
True.
8. What is a Trigger ?
A piece of logic that is executed at or triggered by a SQL *forms event.
9. What are the types of TRIGGERS ?
1. Navigational Triggers.2. Transaction Triggers.
10. What are the different types of key triggers ?
Function KeyKey-functionKey-othersKey-startup
11. What is the difference between a Function Key Trigger and Key Function Trigger ?
Function key triggers are associated with individual SQL*FORMS function keysYou can attach Key function triggers to 10 keys or key sequences that normally do not perform any SQL * FORMS operations. These keys refered as key F0 through key F9.
12. What does an on-clear-block Trigger fire?
It fires just before SQL * forms the current block.
13. How do you trap the error in forms 3.0 ?
using On-Message or On-Error triggers.
14. State the order in which these triggers are executed ?
POST-FIELD,ON-VALIDATE-FIELD,POST-CHANGE and KEY-NEXTFLD.KEY-NEXTFLD,POST-CHANGE, ON-VALIDATE-FIELD, POST-FIELD.
15. What is the usuage of an ON-INSERT,ON-DELETE and ON-UPDATE TRIGGERS ?
These triggers are executes when inserting,deleting and updating operations are performed and can be used to change the default function of insert,delete or update respectively.
For Eg, instead of inserting a row in a table an existing row can be updated in the same table.
16. When will ON-VALIDATE-FIELD trigger executed ?
It fires when a value in a field has been changed and the field status is changed or new and the key has been pressed. If the field status is valid then any further change to the value in the field will not fire the on-validate-field trigger.
17. A query fetched 10 records How many times does a PRE-QUERY Trigger and POST-QUERY Trigger will get executed ?
PRE-QUERY fires once.POST-QUERY fires 10 times.
18. What is the difference between ON-VALIDATE-FIELD trigger and a POST-CHANGE trigger ?
When you changes the Existing value to null, the On-validate field trigger will fire post change trigger will not fire. At the time of execute-query post-chage trigger will fire, on-validate field trigger will not fire.
19. What is the difference between an ON-VALIDATE-FIELD trigger and a trigger ?
On-validate-field trigger fires, when the field Validation status New or changed.Post-field-trigger whenever the control leaving form the field, it will fire.
20. What is the difference between a POST-FIELD trigger and a POST-CHANGE trigger ?
Post-field trigger fires whenever the control leaving from the filed.Post-change trigger fires at the time of execute-query procedure invoked or filed validation status changed.
21. When is PRE-QUERY trigger executed ?
When Execute-query or count-query Package procedures are invoked.
22. Give the sequence in which triggers fired during insert operations, when the following 3 triggers are defined at the smae block level ?a. ON-INSERT b. POST-INSERT c. PRE-INSERT
PRE-INSERT,ON-INSERT & POST-INSERT.
23. Can we use GO-BLOCK package in a pre-field trigger ?
No.
24. Is a Keystartup trigger fires as result of a operator pressing a key explicitly ?
No.
25. How can you execute the user defined triggers in forms 3.0 ?
Execute_Trigger (trigger-name)
26. When does an on-lock trigger fire ?
It will fires whenever SQL * Forms would normally attempt to lock a row.
26. What is Post-Block is a. a. Navigational Trigger.b. Key triggerc. Transaction Trigger.
Navigational Trigger.
27. What is the difference between keystartup and pre-form ?
Key-startup trigger fires after successful navigation into a form.
Pre-form trigger fires before enter into the form.
28. What is the difference between keystartup and pre-form ?
Key-startup triigger fires after successful navigation into a form.Pre-form trigger fires before enter into the form.
PACKAGE PROCEDURE & FUNCTION
29. What is a Package Procedure ?
A Package proecdure is built in PL/SQL procedure.
30. What are the different types of Package Procedure ?
1. Restricted package procedure.2. Unrestricted package proecdure.
31. What is the difference between restricted and unrestricted package procedure ?Restricted package procedure that affects the basic basic functions of SQL * Forms. It cannot used in all triggers execpt key triggers.
Unrestricted package procedure that does not interfere with the basic functions of SQL * Forms it can be used in any triggers.
32. Classify the restricted and unrestricted procedure from the following.a. Callb. User-Exitc. Call-Queryd. Upe. Execute-Queryf. Messageg. Exit-Fromh. Posti. Break
a. Call - unrestrictedb. User Exit - Unrestrictedc. Call_query - Unrestrictedd. Up - Restrictede. Execute Query - Restrictedf. Message - Restrictedg. Exit_form - Restrictedh. Post - Restrictedi. Break - Unrestricted.
33. Can we use a restricted package procedure in ON-VALIDATE-FIELD Trigger ?
No.
34. What SYNCHRONIZE procedure does ?
It synchoronizes the terminal screen with the internal state of the form.
35. What are the unrestricted procedures used to change the popup screen position during run time ?
Anchor-viewResize -ViewMove-View.
36. What Enter package procedure does ?
Enter Validate-data in the current validation unit.
37. What ERASE package procedure does ?
Erase removes an indicated global variable.
38. What is the difference between NAME_IN and COPY ?
Copy is package procedure and writes values into a field.Name in is a package function and returns the contents of the variable to which you apply.
38. Identify package function from the following ?1. Error-Code2. Break3. Call4. Error-text5. Form-failure6. Form-fatal7. Execute-query8. Anchor_View9. Message_code
1. Error_Code2. Error_Text3. Form_Failure4. Form_Fatal5. Message_Code
40. How does the command POST differs from COMMIT ?
Post writes data in the form to the database but does not perform database commitCommit permenently writes data in the form to the database.
41. What the PAUSE package procedure does ?
Pause suspends processing until the operator presses a function key
42. What package procedure is used for calling another form ?
Call (E.g. Call(formname)
43. What package procedure used for invoke sql *plus from sql *forms ?
Host (E.g. Host (sqlplus))
44. Error_Code is a package proecdure ?a. True b. false
False.
45. EXIT_FORM is a restricted package procedure ?a. True b. False
True.
46. When the form is running in DEBUG mode, If you want to examine the values of global variables and other form variables, What package procedure command you would use in your trigger text ?
Break.
SYSTEM VARIABLES
47. List the system variables related in Block and Field?
1. System.block_status2. System.current_block3. System.current_field4. System.current_value5. System.cursor_block6. System.cursor_field7. System.field_status.
48. What is the difference between system.current_field and system.cursor_field ?
1. System.current_field gives name of the field.2. System.cursor_field gives name of the field with block name.
49. The value recorded in system.last_record variable is of typea. Numberb. Booleanc. Character.b. Boolean.
User Exits :
50. What is an User Exits ?
A user exit is a subroutine which are written in programming languages using pro*C pro *Cobol , etc., that link into the SQL * forms executable.
51. What are the type of User Exits ?
ORACLE Precompliers user exitsOCI (ORACLE Call Interface)Non-ORACEL user exits.
Page :
52. What do you mean by a page ?
Pages are collection of display information, such as constant text and graphics.
53. How many pages you can in a single form ?
Unlimited.
54. Two popup pages can appear on the screen at a time ?a. True b. False
a. True.
55.What is the significance of PAGE 0 in forms 3.0 ?
Hide the fields for internal calculation.
56. Deleting a page removes information about all the fields in that page ?a. True. b. False
a. True.
Popup Window :
57. What do you mean by a pop-up window ?
Pop-up windows are screen areas that overlay all or a portion of thedisplay screen when a form is running.
58. What are the types of Pop-up window ?
the pop-up field editorpop-up list of valuespop-up pages.
Alert :
59. What is an Alert ?
An alert is window that appears in the middle of the screen overlaying a portion of the current display.
FORMS 4.0
01. Give the Types of modules in a form?
FormMenuLibrary
02. Write the Abbreviation for the following File Extension1. FMB 2. MMB 3. PLL
FMB ----- Form Module Binary.MMB ----- Menu Module Binary.PLL ------ PL/SQL Library Module Binary.
03. What are the design facilities available in forms 4.0?
Default Block facility.Layout Editor.Menu Editor.Object Lists.Property Sheets.PL/SQL Editor.Tables Columns Browser.Built-ins Browser.
04. What is a Layout Editor?
The Layout Editor is a graphical design facility for creating and arranging items and boilerplate text and graphics objects in your application's interface.
05. BLOCK
05. What do you mean by a block in forms4.0?
Block is a single mechanism for grouping related items into a functional unit for storing,displaying and manipulating records.
06. Explain types of Block in forms4.0?
Base table Blocks.Control Blocks.1. A base table block is one that is associated with a specific database table or view.2. A control block is a block that is not associated with a database table.
ITEMS
07. List the Types of Items?
Text item.Chart item.Check box.Display item.Image item.List item.Radio Group.User Area item.
08. What is a Navigable item?
A navigable item is one that operators can navigate to with the keyboard during default navigation, or that Oracle forms can navigate to by executing a navigationalbuilt-in procedure.
09. Can you change the color of the push button in design time?
No.
10. What is a Check Box?
A Check Box is a two state control that indicates whether a certain condition or value is on or off, true or false. The display state of a check box is always either "checked" or "unchecked".
11. What are the triggers associated with a check box?
Only When-checkbox-activated Trigger associated with a Check box.
PL/SQL
Basiscs of PL/SQL
1. What is PL/SQL ?PL/SQL is a procedural language that has both interactive SQL and procedural programming language constructs such as iteration, conditional branching.
2. What is the basic structure of PL/SQL ?
PL/SQL uses block structure as its basic structure. Anonymous blocks or nested blocks can be used in PL/SQL.
3. What are the components of a PL/SQL block ?
A set of related declarations and procedural statements is called block.
4. What are the components of a PL/SQL Block ?
Declarative part, Executable part and Execption part.
Datatypes PL/SQL
5. What are the datatypes a available in PL/SQL ?
Some scalar data types such as NUMBER, VARCHAR2, DATE, CHAR, LONG, BOOLEAN.Some composite data types such as RECORD & TABLE.
6. What are % TYPE and % ROWTYPE ? What are the advantages of using these over datatypes?
% TYPE provides the data type of a variable or a database column to that variable.
% ROWTYPE provides the record type that represents a entire row of a table or view or columns selected in the cursor.
The advantages are : I. Need not know about variable's data typeii. If the database definition of a column in a table changes, the data type of a variable changes accordingly.
7. What is difference between % ROWTYPE and TYPE RECORD ?
% ROWTYPE is to be used whenever query returns a entire row of a table or view.
TYPE rec RECORD is to be used whenever query returns columns of differenttable or views and variables.
E.g. TYPE r_emp is RECORD (eno emp.empno% type,ename emp ename %type);e_rec emp% ROWTYPEcursor c1 is select empno,deptno from emp;e_rec c1 %ROWTYPE.
8. What is PL/SQL table ?
Objects of type TABLE are called "PL/SQL tables", which are modelled as (but not the same as) database tables, PL/SQL tables use a primary PL/SQL tables can have one column and a primary key.
Cursors
9. What is a cursor ? Why Cursor is required ?
Cursor is a named private SQL area from where information can be accessed. Cursors are required to process rows individually for queries returning multiple rows.
10. Explain the two type of Cursors ?
There are two types of cursors, Implict Cursor and Explicit Cursor.PL/SQL uses Implict Cursors for queries.User defined cursors are called Explicit Cursors. They can be declared and used.
11. What are the PL/SQL Statements used in cursor processing ?
DECLARE CURSOR cursor name, OPEN cursor name, FETCH cursor name INTO or Record types, CLOSE cursor name.
12. What are the cursor attributes used in PL/SQL ?
%ISOPEN - to check whether cursor is open or not% ROWCOUNT - number of rows featched/updated/deleted.% FOUND - to check whether cursor has fetched any row. True if rows are featched.% NOT FOUND - to check whether cursor has featched any row. True if no rows are featched.These attributes are proceded with SQL for Implict Cursors and with Cursor name for Explict Cursors.
13. What is a cursor for loop ?
Cursor for loop implicitly declares %ROWTYPE as loop index,opens a cursor, fetches rows of values from active set into fields in the record and closeswhen all the records have been processed.
eg. FOR emp_rec IN C1 LOOPsalary_total := salary_total +emp_rec sal;END LOOP;
14. What will happen after commit statement ?Cursor C1 isSelect empno,ename from emp;Beginopen C1; loopFetch C1 intoeno.ename;Exit WhenC1 %notfound;-----commit;end loop;end;
The cursor having query as SELECT .... FOR UPDATE gets closed after COMMIT/ROLLBACK.
The cursor having query as SELECT.... does not get closed even after COMMIT/ROLLBACK.
15. Explain the usage of WHERE CURRENT OF clause in cursors ?
WHERE CURRENT OF clause in an UPDATE,DELETE statement refers to the latest row fetched from a cursor.
Database Triggers
16. What is a database trigger ? Name some usages of database trigger ?
Database trigger is stored PL/SQL program unit associated with a specific database table. Usages are Audit data modificateions, Log events transparently, Enforce complex business rules Derive column values automatically, Implement complex security authorizations. Maintain replicate tables.
17. How many types of database triggers can be specified on a table ? What are they ?
Insert Update Delete
Before Row o.k. o.k. o.k.
After Row o.k. o.k. o.k.
Before Statement o.k. o.k. o.k.
After Statement o.k. o.k. o.k.
If FOR EACH ROW clause is specified, then the trigger for each Row affected by the statement.
If WHEN clause is specified, the trigger fires according to the retruned boolean value.
18. Is it possible to use Transaction control Statements such a ROLLBACK or COMMIT in Database Trigger ? Why ?
It is not possible. As triggers are defined for each table, if you use COMMIT of ROLLBACK in a trigger, it affects logical transaction processing.
19. What are two virtual tables available during database trigger execution ?
The table columns are referred as OLD.column_name and NEW.column_name.For triggers related to INSERT only NEW.column_name values only available.For triggers related to UPDATE only OLD.column_name NEW.column_name values only available.For triggers related to DELETE only OLD.column_name values only available.
20. What happens if a procedure that updates a column of table X is called in a database trigger of the same table ?
Mutation of table occurs.
21. Write the order of precedence for validation of a column in a table ?I. done using Database triggers.ii. done using Integarity Constraints.
I & ii.
Exception :
22. What is an Exception ? What are types of Exception ?
Exception is the error handling part of PL/SQL block. The types are Predefined and user_defined. Some of Predefined execptions are. CURSOR_ALREADY_OPENDUP_VAL_ON_INDEXNO_DATA_FOUNDTOO_MANY_ROWSINVALID_CURSORINVALID_NUMBERLOGON_DENIEDNOT_LOGGED_ONPROGRAM-ERRORSTORAGE_ERRORTIMEOUT_ON_RESOURCEVALUE_ERRORZERO_DIVIDEOTHERS.
23. What is Pragma EXECPTION_INIT ? Explain the usage ?
The PRAGMA EXECPTION_INIT tells the complier to associate an exception with an oracle error. To get an error message of a specific oracle error.
e.g. PRAGMA EXCEPTION_INIT (exception name, oracle error number)
24. What is Raise_application_error ?
Raise_application_error is a procedure of package DBMS_STANDARD which allows to issue an user_defined error messages from stored sub-program or database trigger.
25. What are the return values of functions SQLCODE and SQLERRM ?
SQLCODE returns the latest code of the error that has occured.SQLERRM returns the relevant error message of the SQLCODE.
26. Where the Pre_defined_exceptions are stored ?
In the standard package.
Procedures, Functions & Packages ;
27. What is a stored procedure ?
A stored procedure is a sequence of statements that perform specific function.
28. What is difference between a PROCEDURE & FUNCTION ?
A FUNCTION is alway returns a value using the return statement.A PROCEDURE may return one or more values through parameters or may not return at all.
29. What are advantages fo Stored Procedures /
Extensibility,Modularity, Reusability, Maintainability and one time compilation.
30. What are the modes of parameters that can be passed to a procedure ?
IN,OUT,IN-OUT parameters.
31. What are the two parts of a procedure ?
Procedure Specification and Procedure Body.
32. Give the structure of the procedure ?
PROCEDURE name (parameter list.....)islocal variable declarations
BEGINExecutable statements.Exception.exception handlers
end;
33. Give the structure of the function ?
FUNCTION name (argument list .....) Return datatype islocal variable declarationsBeginexecutable statementsExceptionexecution handlersEnd;
34. Explain how procedures and functions are called in a PL/SQL block ?
Function is called as part of an expression.sal := calculate_sal ('a822');procedure is called as a PL/SQL statementcalculate_bonus ('A822');
35. What is Overloading of procedures ?
The Same procedure name is repeated with parameters of different datatypes and parameters in different positions, varying number of parameters is called overloading of procedures.
e.g. DBMS_OUTPUT put_line
36. What is a package ? What are the advantages of packages ?
Package is a database object that groups logically related procedures.The advantages of packages are Modularity, Easier Applicaton Design, Information. Hiding,. reusability and Better Performance.
37.What are two parts of package ?
The two parts of package are PACKAGE SPECIFICATION & PACKAGE BODY.
Package Specification contains declarations that are global to the packages and local to the schema.Package Body contains actual procedures and local declaration of the procedures and cursor declarations.
38. What is difference between a Cursor declared in a procedure and Cursor declared in a package specification ?
A cursor declared in a package specification is global and can be accessed by other procedures or procedures in a package.A cursor declared in a procedure is local to the procedure that can not be accessed by other procedures.
39. How packaged procedures and functions are called from the following?a. Stored procedure or anonymous blockb. an application program such a PRC *C, PRO* COBOLc. SQL *PLUS
a. PACKAGE NAME.PROCEDURE NAME (parameters);variable := PACKAGE NAME.FUNCTION NAME (arguments);EXEC SQL EXECUTEb.BEGINPACKAGE NAME.PROCEDURE NAME (parameters)variable := PACKAGE NAME.FUNCTION NAME (arguments);END;END EXEC;c. EXECUTE PACKAGE NAME.PROCEDURE if the procedures does not have anyout/in-out parameters. A function can not be called.
40. Name the tables where characteristics of Package, procedure and functions are stored ?
User_objects, User_Source and User_error.
FORMS4.0
12. what is a display item?
Display items are similar to text items but store only fetched or assigned values. Operators cannot navigate to a display item or edit the value it contains.
13. What is a list item?
It is a list of text elements.
14. What are the display styles of list items?
Poplist, No text Item displayed in the list item.Tlist, No element in the list is highlighted.
15. What is a radio Group?
Radio groups display a fixed no of options that are mutually Exclusive .User can select one out of n number of options.
16. How many maximum number of radio buttons can you assign to a radio group?
Unlimited no of radio buttons can be assigned to a radio group
17. can you change the default value of the radio button group at run time?
No.
18.What triggers are associated with the radio group?
Only when-radio-changed trigger associated with radio group
Visual Attributes.
19. What is a visual attribute?
Visual Attributes are the font, color and pattern characteristics of objects that operators see and intract with in our application.
20. What are the types of visual attribute settings?
Custom Visual attributesDefault visual attributesNamed Visual attributes.
Window
21. What is a window?
A window, byitself , can be thought of as an empty frame. The frame provides a way to intract with the window, including the ability to scroll, move, and resize the window. The content of the window ie. what is displayed inside the frame is determined by the canvas View or canvas-views displayed in the window at run-time.
22. What are the differrent types of windows?
Root window, secondary window.
23. Can a root window be made modal?
No.
24. List the buil-in routine for controlling window during run-time?
Find_window,get_window_property,hide_window,move_window,resize_window,set_window_property,show_View
25. List the windows event triggers available in Forms 4.0?
When-window-activated, when-window-closed, when-window-deactivated,when-window-resized
26. What built-in is used for changing the properties of the window dynamically?
Set_window_property
Canvas-View
27. What is a canvas-view?
A canvas-view is the background object on which you layout the interface items (text-items, check boxes, radio groups, and so on.) and boilerplate objects that operators see and interact with as they run your form. At run-time, operators can see only those items that have been assiged to a specific canvas. Each canvas, in term, must be displayed in a specfic window.
28. Give the equivalent term in forms 4.0 for the following.Page, Page 0?
Page - Canvas-ViewPage 0 - Canvas-view null.
29. What are the types of canvas-views?
Content View, Stacked View.
30. What is the content view and stacked view?
A content view is the "Base" view that occupies the entire content pane of the window in which it is displayed.A stacked view differs from a content canvas view in that it is not the base view for the window to which it is assigned
31. List the built-in routines for the controlling canvas views during run-time?
Find_canvasGet-Canvas_propertyGet_view_propertyHide_ViewReplace_content_viewScroll_viewSet_canvas_propertySet_view_propertyShow_view
Alert
32. What is an Alert?
An alert is a modal window that displays a message notifies the operator of some application condition
33. What are the display styles of an alert?
Stop, Caution, note
34. Can you attach an alert to a field?
No
35. What built-in is used for showing the alert during run-time?
Show_alert.
36. Can you change the alert messages at run-time?If yes, give the name of th built-in to chage the alert messages at run-time.
Yes. Set_alert_property.
37. What is the built-in function used for finding the alert?
Find_alert
Editors
38. List the editors availables in forms 4.0?
Default editorUser_defined editorssystem editors.
39. What buil-in routines are used to display editor dynamicaly?
Edit_text itemshow_editor
LOV
40. What is an Lov?
A list of values is a single or multi column selection list displayed ina pop-up window
41. Can you attach an lov to a field at design time?
Yes.
42. Can you attach an lov to a field at run-time? if yes, give the build-in name.
Yes. Set_item_proprety
43. What is the built-in used for showing lov at runtime?
Show_lov
44. What is the built-in used to get and set lov properties during run-time?
Get_lov_propertySet_lov_property
Record Group
45. What is a record Group?
A record group is an internal oracle forms data structure that has a simillar column/row frame work to a database table
46. What are the different type of a record group?
Query record groupStatic record groupNon query record group
47. Give built-in routine related to a record groups?
Create_group (Function)Create_group_from_query(Function)Delete_group(Procedure)Add_group_column(Function)Add_group_row(Procedure)Delete_group_row(Procedure)Populate_group(Function)Populate_group_with_query(Function)Set_group_Char_cell(procedure)
48. What is the built_in routine used to count the no of rows in a group?
Get_group _row_count
System Variables
49. List system variables available in forms 4.0, and not available in forms 3.0?
System.cordination_operationSystem Date_thresholdSystem.effective_DateSystem.event_windowSystem.suppress_working
50. System.effective_date system variable is read only True/False
False
51. What is a library in Forms 4.0?
A library is a collection of Pl/SQL program units, including user named procedures, functions & packages
52. Is it possible to attach same library to more than one form?
Yes
53. Explain the following file extention related to library?.pll,.lib,.pld
The library pll files is a portable design file comparable to an fmb form fileThe library lib file is a plat form specific, generated library file comparable to a fmx form fileThe pld file is Txt format file and can be used for source controlling your library files
Parameter
54. How do you pass the parameters from one form to another form?
To pass one or more parameters to a called form, the calling form must perform the following steps in a trigger or user named routine excute the create_parameter_list built_in function to programatically.Create a parameter list to execute the add parameter built_in procedure to add one or more parameters list.Execute the call_form, New_form or run_product built_in procedure and include the name or id of the parameter list to be passed to the called form.
54. What are the built-in routines is available in forms 4.0 to create and manipulate a parameter list?
Add_parameterCreate_Parameter_listDelete_parameterDestroy_parameter_listGet_parameter_attrGet_parameter_listset_parameter_attr
55. What are the two ways to incorporate images into a oracle forms application?
Boilerplate ImagesImage_items
56. How image_items can be populate to field in forms 4.0?
A fetch from a long raw database column PL/Sql assignment to executing the read_image_file built_in procedure to get an image from the file system.
57. What are the triggers associated with the image item?
When-Image-activated(Fires when the operator double clicks on an image Items)When-image-pressed(fires when the operator selects or deselects the image item)
58. List some built-in routines used to manipulate images in image_item?
Image_addImage_andImage_subtractImage_xorImage_zoom
59. What are the built_in used to trapping errors in forms 4?
Error_type return characterError_code return numberError_text return charDbms_error_code return no.Dbms_error_text return char
60. What is a predefined exception available in forms 4.0?
Raise form_trigger_failure
61. What are the menu items that oracle forms 4.0 supports?
Plain, Check,Radio, Separator, Magic
FORMS4.5
object groups
01. what ia an object groups?
An object group is a container for a group of objects, you define an object group when you want to package related objects. so that you copy or reference them in another modules.
02. what are the different objects that you cannot copy or reference in object groups?
objects of differnt modulesanother object groupsindividual block dependent itemsprogram units.
canvas views
03. what are different types of canvas views?
content canvas viewsstacked canvas viewshorizontal toolbarvertical toolbar.
04. explain about content canvas views?
Most Canvas views are content canvas views a content canvas view is the "base" view that occupies the entire content pane of the window in which it is displayed.
05. Explain about stacked canvas views?
Stacked canvas view is displayed in a window on top of, or "stacked" on the content canvas view assigned to that same window. Stacked canvas views obscure some part of the underlying content canvas view, and or often shown and hidden programmatically.
06. Explain about horizontal, Vertical tool bar canvas views?
Tool bar canvas views are used to create tool bars for individual windows Horizontal tool bars are display at the top of a window, just under its menu bar.Vertical Tool bars are displayed along the left side of a window
07. Name of the functions used to get/set canvas properties?
Get_view_property, Set_view_property
Windows
07. What is relation between the window and canvas views?
Canvas views are the back ground objects on which you place the interface items (Text items), check boxes, radio groups etc.,) and boilerplateobjects (boxes, lines, images etc.,) that operators interact with us they run your form . Each canvas views displayed in a window.
08. What are the different modals of windows?
Modalless windowsModal windows
09. What are modalless windows?
More than one modelless window can be displayed at the same time, and operators can navigate among them if your application allows them to do so . On most GUI platforms, modelless windows can also be layered to appear either in front of or behind other windows.
10. What are modal windows?
Modal windows are usually used as dialogs, and have restricted functionality compared to modelless windows. On some platforms for example operators cannot resize, scroll or iconify a modal window.
11. How do you display console on a window ?
The console includes the status line and message line, and is displayed at the bottom of the window to which it is assigned.To specify that the console should be displayed, set the console window form property to the name of any window in the form. To include the console, set console window to Null.
12. What is the remove on exit property?
For a modelless window, it determines whether oracle forms hides the window automatically when the operators navigates to an item in the another window.
13. How many windows in a form can have console?
Only one window in a form can display the console, and you cannot chage the console assignment at runtime.
14. Can you have more than one content canvas view attached with a window?
Yes.Each window you create must have atleast one content canvas view assigned to it. You can also create a window that has manipulate contant canvas view. At run time only one of the content canvas views assign to a window is displayed at a time.
15. What are the different window events activated at runtimes?
When_window_activatedWhen_window_closedWhen_window_deactivatedWhen_window_resizedWithin this triggers, you can examine the built in system variable system.event_window to determine the name of the window for which the trigger fired.
Modules
27. What are different types of modules available in oracle form?
Form module - a collection of objects and code routinesMenu modules - a collection of menus and menu item commands that together make up an application menulibrary module - a collectio of user named procedures, functions and packages that can be called from other modules in the application
18. What are the default extensions of the files careated by forms modules?
.fmb - form module binary.fmx - form module executable
19. What are the default extentions of the files created by menu module?
.mmb, .mmx
20 What are the default extension of the files created by library module?
The default file extensions indicate the library module type and storage format.pll - pl/sql library module binary
Master Detail
21. What is a master detail relationship?
A master detail relationship is an association between two base table blocks- a master block and a detail block. The relationship between the blocks reflects a primary key to foreign key relationship between the tables on which the blocks are based.
22. What is coordination Event?
Any event that makes a different record in the master block the current record is a coordination causing event.
23. What are the two phases of block coordination?
There are two phases of block coordination: the clear phase and the population phase. During, the clear phase, Oracle Forms navigates internally to the detail block and flushes the obsolete detail records. During the population phase, Oracle Forms issues a SELECT statement to repopulate the detail block with detail records associated witjh the new master record. These operations are accomplished through the execution of triggers.
24. What are Most Common types of Complex master-detail relationships?
There are three most common types of complex master-detail relationships:master with dependent detailsmaster with independent detailsdetail with two masters
25. What are the different types of Delete details we can establish in Master-Details?CascadeIsolateNon-isolote
26. What are the different defaust triggers created when Master Deletes Property is set to Non-isolated?Master Delets Property Resulting Triggers----------------------------------------------------Non-Isolated(the default) On-Check-Delete-MasterOn-Clear-DetailsOn-Populate-Details
26. Whar are the different default triggers created when Master Deletes Property is set to Cascade?Ans: Master Deletes Property Resulting Triggers---------------------------------------------------Cascading On-Clear-DetailsOn-Populate-DetailsPre-delete
28. What are the different default triggers created when Master Deletes Property is set to isolated?
Master Deletes Property Resulting Triggers---------------------------------------------------Isolated On-Clear-DetailsOn-Populate-Details
29. What are the Coordination Properties in a Master-Detail relationship?The coordination properties areDeferredAuto-QueryThese Properties determine when the population phase of blockcoordination should occur.
30. What are the different types of Coordinations of the Master with the Detail block?
42. What is the User-Named Editor?
A user named editor has the same text editing functionality as the default editor, but, becaue it is a named object, you can specify editor attributes such as windows display size, position, and title.
43. What are the Built-ins to display the user-named editor?
A user named editor can be displayed programmatically with the built in procedure SHOW-EDITOR, EDIT_TETITEM independent of any particular text item.
44. What is the difference between SHOW_EDITOR and EDIT_TEXTITEM?
Show editor is the generic built_in which accepts any editor name and takes some input string and returns modified output string. Whereas the edit_textitem built_in needs the input focus to be in the text item before the built_in is excuted.
45. What is an LOV?An LOV is a scrollable popup window that provides the operator with either a single or multi column selection list.
46. What is the basic data structure that is required for creating an LOV? Record Group.
47. What is the "LOV of Validation" Property of an item? What is the use of it?When LOV for Validation is set to True, Oracle Forms compares the current value of the text item to the values in the first column displayed in the LOV.Whenever the validation event occurs.If the value in the text item matches one of the values in the first column of the LOV, validation succeeds, the LOV is not displayed, and processing continues normally.If the value in the text item does not match one of the values in the first column of the LOV, Oracle Forms displays the LOV and uses the text item value as the search criteria to automatically reduce the list.
48. What are the built_ins used the display the LOV?
Show_lovList_values
49. What are the built-ins that are used to Attach an LOV programmatically to an item?
set_item_propertyget_item_property(by setting the LOV_NAME property)
50. What are the built-ins that are used for setting the LOV properties at runtime?
get_lov_propertyset_lov_property
51. What is a record group?
A record group is an internal Oracle Forms that structure that hs a column/row framework similar to a database table. However, unlike database tables, record groups are separate objects that belong to the form module which they are defined.
52. How many number of columns a record group can have?
A record group can have an unlimited number of columns of type CHAR, LONG, NUMBER, or DATE provided that the total number of column does not exceed 64K.
53. What is the Maximum allowed length of Record group Column?
Record group column names cannot exceed 30 characters.
54. What are the different types of Record Groups?
Query Record GroupsNonQuery Record GroupsState Record Groups
55. What is a Query Record Group?
A query record group is a record group that has an associated SELECT statement. The columns in a query record group derive their default names, data types, had lengths from the database columns referenced in the SELECT statement. The records in query record group are the rows retrieved by the query associated with that record group.
56. What is a Non Query Record Group?
A non-query record group is a group that does not have an associated query, but whose structure and values can be modified programmatically at runtime.
57. What is a Static Record Group?
A static record group is not associated with a query, rather, you define its structure and row values at design time, and they remain fixed at runtime.
58. What are the built-ins used for Creating and deleting groups?
CREATE-GROUP (function)CREATE_GROUP_FROM_QUERY(function)DELETE_GROUP(procedure)
59.What are the built -ins used for Modifying a group's structure?
ADD-GROUP_COLUMN (function)ADD_GROUP_ROW (procedure)DELETE_GROUP_ROW(procedure)
60. POPULATE_GROUP(function)POPULATE_GROUP_WITH_QUERY(function)SET_GROUP_CHAR_CELL(procedure)SET_GROUP_DATE_CELL(procedure)SET_GROUP_NUMBER_CELL(procedure)
61. What are the built-ins used for Getting cell values?
GET_GROUP_CHAR_CELL (function)GET_GROUP_DATE_CELL(function)GET_GROUP_NUMBET_CELL(function)
62. What are built-ins used for Processing rows?
GET_GROUP_ROW_COUNT(function)GET_GROUP_SELECTION_COUNT(function)GET_GROUP_SELECTION(function)RESET_GROUP_SELECTION(procedure)SET_GROUP_SELECTION(procedure)UNSET_GROUP_SELECTION(procedure)
63. What are the built-ins used for finding Object ID function?
FIND_GROUP(function)FIND_COLUMN(function)
64. Use the ADD_GROUP_COLUMN function to add a column to a record group that was created at design time.I) TRUE II)FALSE
II) FALSE
65. Use the ADD_GROUP_ROW procedure to add a row to a static record group
I) TRUE II)FALSEI) FALSE
61. What are the built-in used for getting cell values?
Get_group_char_cell(function)Get_group_date_cell(function)Get_group_number_cell(function)
62. What are the built-ins used for processing rows?
Get_group_row_count(function)Get_group_selection_count(function)Get_group_selection(function)Reset_group_selection(procedure)Set_group_selection(procedure)Unset_group_selection(procedure)
63. What are the built-ins used for finding object ID functions?
Find_group(function)Find_column(function)
64. Use the add_group_column function to add a column to record group that was created at a design time?
False.
65. Use the Add_group_row procedure to add a row to a static record group 1. true or false?
False.
parameters
66. What are parameters?
Parameters provide a simple mechanism for defining and setting the valuesof inputs that are required by a form at startup. Form parameters are variables of type char,number,date that you define at design time.
67. What are the Built-ins used for sending Parameters to forms?
You can pass parameter values to a form when an application executes the call_form, New_form, Open_form or Run_product.
68. What is the maximum no of chars the parameter can store?
The maximum no of chars the parameter can store is only valid for char parameters, which can be upto 64K. No parameters default to 23Bytes and Date parameter default to 7Bytes.
69. How do you call other Oracle Products from Oracle Forms?
Run_product is a built-in, Used to invoke one of the supported oracle tools products and specifies the name of the document or module to be run. If the called product is unavailable at the time of the call, Oracle Forms returns a message to the opertor.
70. How do you reference a Parameter?
In Pl/Sql, You can reference and set the values of form parameters using bind variables syntax. Ex. PARAMETER name = '' or :block.item = PARAMETER Parameter name
71. How do you reference a parameter indirectly?
To indirectly reference a parameter use the NAME IN, COPY 'built-ins to indirectly set and reference the parameters value' Example name_in ('capital parameter my param'), Copy ('SURESH','Parameter my_param')
72. What are the different Parameter types?
Text ParametersData Parameters
73. When do you use data parameter type?
When the value of a data parameter being passed to a called product is always the name of the record group defined in the current form. Data parameters are used to pass data to produts invoked with the run_product built-in subprogram.
74. Can you pass data parametrs to forms?
No.
IMAGES
75. What are different types of images?
Boiler plate imagesImage Items
76. What is the difference between boiler plat images and image items?
Boiler plate Images are static images (Either vector or bit map) that you import from the file system or database to use a grapical elements in your form, such as company logos and maps Image items are special types of interface controls that store and display either vector or bitmap images. Llike other items that store values, image items can be either base table items(items that relate directly to database columns) or control items. The definition of an image item is stored as part of the form module FMB and FMX files, but no image file is actualy associated with an image item until the item is populate at run time.
77. What are the trigger associated with image items?
When-image-activated fires when the operators double clicks on an image item when-image-pressed fires when an operator clicks or double clicks on an image item
78. What is the use of image_zoom built-in?
To manipulate images in image items.
WORKING WITH MULTIPLE FORMS
79. How do you create a new session while open a new form?
Using open_form built-in setting the session option Ex. Open_form('Stocks ',active,session). when invoke the mulitiple forms with open form and call_form in the same application, state whether the following are true/False
80. Any attempt to navigate programatically to disabled form in a call_form stack is allowed?
False
81. An open form can not be execute the call_form procedure if you chain of called forms has been initiated by another open form?
True
82. When a form is invoked with call_form, Does oracle forms issues a save point?
True
Mouse Operations
83. What are the various sub events a mouse double click event involves?
Double clicking the mouse consists of the mouse down, mouse up, mouse click, mouse down & mouse up events.
84, State any three mouse events system variables?
System.mouse_button_pressedSystem.mouse_button_shift_statesystem.mouse_itemsystem.mouse_canvassystem.mouse_record
OLE
85. What is an OLE?
Object Linking & Embadding provides you with the capability to integrate objects from many Ms-Windows applications into a single compound document creating integrated applications enables you to use the features form .
86. What is the difference between object embedding & linking in Oracle forms?
In Oracle forms, Embedded objects become part of the form module, and linked objects are references from a form module to a linked source file.
87. What is the difference between OLE Server & Ole Container?
An Ole server application creates ole Objects that are embedded or linked in ole Containers ex. Ole servers are ms_word & ms_excell. OLE containers provide a place to store, display and manipulate objects that are created by ole server applications. Ex. oracle forms is an example of an ole Container.
88. What are the different styles of actvation of ole Objects?
In place activationExternal activation
ViSUAL Attributes & property clauses
89. What are visual attributes?
Visual attributes are the font, color, pattern proprities that you set for form and menu objects that appear in your application interface.
90. What is a property clause?
A property clause is a named object that contains a list of properties and thier settings. Once you create a property clause you can base other object on it. An object based on a property can inherit the setting of any property in the clause that makes sense for that object.
91. Can a property clause itself be based on a property clause?
Yes
92. What are the important difference between property clause and visual attributes?
Named visual attributes differed only font, color & pattern attributes, property clauses can contain this and any other properties. You can change the appearance of objects at run time by changing the named visual attributes programatically , property clause assignments cannot be changed programatically. When an object is inheriting from both a property clause and named visual attribute, the named visual attribute settings take precedence, and any visual attribute properties in the class are ignored.
Form Build-ins
93. What is a Text_io Package?
It allows you to read and write information to a file in the file system.
94. What is an User_exit?
Calls the user exit named in the user_exit_string. Invokes a 3Gl programe by name which has been properly linked into your current oracle forms executable.
95. What is synchronize?
It is a terminal screen with the internal state of the form. It updates the screen display to reflect the information that oracle forms has in its internal representation of the screen.
96. What is forms_DDL?
Issues dynamic Sql statements at run time, including server side pl/SQl and DDL
Triggers
97. What is WHEN-Database-record trigger?
Fires when oracle forms first marks a record as an insert or an update. The trigger fires as soon as oracle forms determines through validation that the record should be processed by the next post or commit as an insert or update. c generally occurs only when the operators modifies the first item in the record, and after the operator attempts to navigate out of the item.
98. What are the master-detail triggers?
On-Check_delete_masterOn_clear_detailsOn_populate_details
99. What is the difference between $$DATE$$ & $$DBDATE$$
$$DBDATE$$ retrieves the current database date$$date$$ retrieves the current operating system date.
100. What is system.coordination_operation?
It represents the coordination causing event that occur on the master block in master-detail relation.
101. What are the difference between lov & list item?
Lov is a property where as list item ias an item. A list item can have only one column, lov can have one or more columns.
102. What are the different display styles of list items?
Pop_listText_listCombo box
103. What is pop list?
The pop list style list item appears initially as a single field (similar to a text item field). When the operator selects the list icon, a list of available choices appears.
104. What is a text list?
The text list style list item appears as a rectangular box which displays the fixed number of values. When the text list contains values that can not be displayed, a vertical scroll bar appears, allowing the operator to view and select undisplayed values.
105. What is a combo box?
A combo box style list item combines the features found in list and text item. Unlike the pop list or the text list style list items, the combo box style list item will both display fixed values and accept one operator entered value.
106. What are display items?
Display items are similar to text items with the exception that display items only store and display fetched or assigned values.Display items are generaly used as boilerplate or conditional text.
107. What is difference between open_form and call_form?
when one form invokes another form by executing open_form the first form remains displayed,and operators can navigate between the forms as desired. when one form invokes another form by executing call_form,the called form is modal with respect to the calling form.That is, any windows that belong to the calling form are disabled, and operators cannot navigate to them until they first exit the called form.
108. What is new_form built-in?
When one form invokes another form by executing new_form oracle form exits the first form and releases its memory before loading the new form calling new form completely replace the first with the second. If there are changes pending in the first form,the operator will be prompted to save them before the new form is loaded.
109. What is a library?
A library is a collection of subprograms including user named procedures, functions and packages.
110. What is the advantage of the library?
Library's provide a convenient means of storing client-side program units and sharing them among multipule applications. Once you create a library, you can attach it to any other form,menu,or library modules. When you can call library program units from triggers menu items commands and user named routine, you write in the modules to which you have attach the library.when a library attaches another library ,program units in the first library can reference program units in the attached library. Library support dynamic loading-that is library program units are loaded into an application only when needed. This can significantly reduce the run-time memory requirements of an applications.
111. What is strip sources generate options?
Removes the source code from the library file and generates a library files that contains only pcode.The resulting file can be used for final deployment, but can not be subsequently edited in the designer.
ex. f45gen module=old_lib.pll userid=scott/tigerstrip_source YES output_file
112.What are the vbx controls?
Vbx control provide a simple mehtod of buildig and enhancing user interfaces.The controls can use to obtain user inputs and display program outputs.vbx control where originally develop as extensions for the ms visual basic environments and include such items as sliders,grides and knobs.
113. What is a timer?
Timer is a "internal time clock" that you can programmatically create to perform an action each time the timer expires.
114. What are built-ins associated with timers?
find_timercreate_timerdelete_timer
115. what are difference between post database commit and post-form commit?
Post-form commit fires once during the post and commit transactions process, after the database commit occures. The post-form-commit trigger fires after inserts,updates and deletes have been posted to the database but before the transactions have been finalished in the issuing the command.The post-database-commit trigger fires after oracle forms issues the commit to finalished transactions.
116. What is a difference between pre-select and pre-query?
Fires during the execute query and count query processing after oracle forms constructs the select statement to be issued, but before the statement is actually issued.
The pre-query trigger fires just before oracle forms issues the select statement to the database after the operator as define the example records by entering the query criteria in enter query mode.
Pre-query trigger fires before pre-select trigger.
117. What is trigger associated with the timer?
When-timer-expired.
118 What is the use of transactional triggers?
Using transactional triggers we can control or modify the default functionality of the oracle forms.
REPORTS
1. What are the different file extensions that are created by oracle reports?
Rep file and Rdf file.
2. From which designation is it preferred to send the output to the printed?
Previewer.
3. Is it possible to disable the parameter from while running the report? Yes
4. What is lexical reference?How can it be created?
Lexical reference is place_holder for text that can be embedded in a sqlstatements.A lexical reference can be created using & before the column orparameter name.
5. What is bind reference and how can it carate?
Bind reference are used to replace the single value in sql,pl/sqlstatements a bind reference can be careated using a (:) before a column ora parameter name.
6.What use of command line parameter cmd file?
It is a command line argument that allows you to specify a file that contain a set of arguments for r20run.
7.Where is a procedure return in an external pl/sql library executed at the client or at the server?
At the client.
8. Where is the external query executed at the client or the server?
At the server.
9. What are the default parameter that appear at run time in the parameter screen?
Destype and Desname.
10. Which parameter can be used to set read level consistency across multiple queries?
Read only.
11. What is term?
The term is terminal definition file that describes the terminal form which you are using r20run.
12. What is use of term?
The term file which key is correspond to which oracle report functions.
13. Is it possible to insert comments into sql statements return in the data model editor?
Yes.
14. If the maximum record retrieved property of the query is set to 10 then a summary value will be calculated?
Only for 10 records.
15. What are the sql clauses supported in the link property sheet?
Where startwith having.
16. To execute row from being displayed that still use column in the row which property can be used?
Format trigger.
17. Is it possible to set a filter condition in a cross product group in matrix reports?
No.
18. If a break order is set on a column would it effect columns which are under the column? No.
19. With which function of summary item is the compute at options required?
percentage of total functions.
20. What is the purpose of the product order option in the column property sheet?
To specify the order of individual group evaluation in a cross products.
21.Can a formula column be obtained through a select statement?
Yes.
22.Can a formula column refered to columns in higher group?
Yes.
23. How can a break order be created on a column in an existing group?
By dragging the column outside the group.
24. What are the types of calculated columns available?
Summary, Formula, Placeholder column.
25. What is the use of place holder column?
A placeholder column is used to hold a calculated values at a specified place rather than allowing is to appear in the actual row where it has to appeared.
26. What is the use of hidden column?
A hidden column is used to when a column has to embedded into boilerplate text.
27. What is the use of break group?
A break group is used to display one record for one group ones.While multiple related records in other group can be displayed.
28. If two groups are not linked in the data model editor, What is the hierarchy between them?
Two group that is above are the left most rank higher than the group that is to right or below it.
29.The join defined by the default data link is an outer join yes or no?
Yes.
30. How can a text file be attached to a report while creating in the report writer?
By using the link file property in the layout boiler plate property sheet.
31. Can a repeating frame be careated without a data group as a base?
No.
32. Can a field be used in a report wihtout it appearing in any data group?
Yes.
33. For a field in a repeating frame, can the source come from the column which does not exist in the data group which forms the base for the frame?
Yes.
34. Is it possible to center an object horizontally in a repeating frame that has a variable horizontal size?
Yes.
35. If yes,how?
By the use anchors.
36. What are the two repeating frame always associated with matrix object?
One down repeating frame below one across repeating frame.
37. Is it possible to split the printpreviewer into more than one region?
Yes.
38. Does a grouping done for objects in the layout editor affect the grouping done in the datamodel editor?
No.
39. How can a square be drawn in the layout editor of the report writer?
By using the rectangle tool while pressing the (Constraint) key.
40. To display the page no. for each page on a report what would be the source & logical page no. or & of physical page no.?
& physical page no.
41. What does the term panel refer to with regard to pages?
A panel is the no. of physical pages needed to print one logical page.
42. What is an anchoring object & what is its use?
An anchoring object is a print condition object which used to explicitly or implicitly anchor other objects to itself.
43. What is a physical page ? & What is a logical page ?
A physical page is a size of a page. That is output by the printer. Thelogical page is the size of one page of the actual report as seen in thePreviewer.
44. What is the frame & repeating frame?
A frame is a holder for a group of fields. A repeating frame is used todisplay a set of records when the no. of records that are to displayed isnot known before.
REPORT TRIGGERS.
45. What are the triggers available in the reports?
Before report, Before form, After form , Between page, After report.
46. Does a Before form trigger fire when the parameter form is suppressed.
Yes.
47. At what point of report execution is the before Report trigger fired?
After the query is executed but before the report is executed and therecords are displayed.
48. Is the After report trigger fired if the report execution fails?
Yes.
49. Give the sequence of execution of the various report triggers?
Before form , After form , Before report, Between page, After report.
50. Is it possible to modify an external query in a report which containsit?
No.
51. What are the ways to monitor the performance of the report?
Use reports profile executable statement.Use SQL trace facility.
52. Why is it preferable to create a fewer no. of queries in the datamodel.
Because for each query, report has to open a separate cursor and has torebind, execute and fetch data.
53. What are the various methods of performing a calculation in a report ?
1. Perform the calculation in the SQL statements itself.2. Use a calculated / summary column in the data model.
54. Which of the above methods is the faster method?
performing the calculation in the query is faster.
55. Why is a Where clause faster than a group filter or a format trigger?
Because, in a where clause the condition is applied during data retrievalthan after retrieving the data.
56. What is the main diff. bet. Reports 2.0 & Reports 2.5?
Report 2.5 is object oriented.
57. What is the diff. bet. setting up of parameters in reports 2.0 reports2.5?
LOVs can be attached to parameters in the reports 2.5 parameter form.
58. How is link tool operation different bet. reports 2 & 2.5?
In Reports 2.0 the link tool has to be selected and then two fields to belinked are selected and the link is automatically created. In 2.5 the firstfield is selected and the link tool is then used to link the first field tothe second field.
REPORT 2.5 SPECIFIC ISSUES.
59.What are the two types views available in the object navigator(specificto report 2.5)?
View by structure and view by type .
60. Which of the two views should objects according to possession?
view by structure.
61.How is possible to restrict the user to a list of values while enteringvalues for parameters?
By setting the Restrict To List property to true in the parameter propertysheet.
62. How is it possible to select generate a select ste. for the query inthe query property sheet?
By using the tables/columns button and then specifying the table and thecolumn names.
63. If a parameter is used in a query without being previously defined,what diff. exist betw. report 2.0 and 2.5 when the query is applied?
While both reports 2.0 and 2.5 create the parameter, report 2.5 gives amessage that a bind parameter has been created.
64. Do user parameters appear in the data modal editor in 2.5?
No.
65.What is the diff. when confine mode is on and when it is off?
When confine mode is on, an object cannot be moved outside its parent inthe layout.
66. What is the diff. when Flex mode is mode on and when it is off?
When flex mode is on, reports automatically resizes the parent when thechild is resized.
67. How can a button be used in a report to give a drill down facility?
By setting the action asscoiated with button to Execute pl/sql option andusing the SRW.Run_report function.
68. What are the two ways by which data can be generated for a parameter'slist of values?
1. Using static values.2. Writing select statement.
69. What are the two panes that Appear in the design time pl/sqlinterpreter?
1.Source pane. 2. Interpreter pane
70. What are three panes that appear in the run time pl/sql interpreter?
1.Source pane. 2. interpreter pane. 3. Navigator pane.
CROSS PRODUCTS AND MATRIX REPORTS
71. How can a cross product be created?
By selecting the cross products tool and drawing a new group surroundingthe base group of the cross products.
72. How can a group in a cross products be visually distinguished from agroup that does not form a cross product?
A group that forms part of a cross product will have a thicker border.
73. Atleast how many set of data must a data model have before a data modelcan be base on it?
Four.
74. Is it possible to have a link from a group that is inside a crossproduct to a group outside ? (Y/N)
No.
75. Is it possible to link two groups inside a cross products after thecross products group has been created?
No.
76. What is an user exit used for?
A way in which to pass control (and possibly arguments ) form Oracle reportto another Oracle products of 3 GL and then return control ( and ) backto Oracle reprots.
77. What are the three types of user exits available ?
Oracle Precompiler exits, Oracle call interface,NonOracle user exits.
78. How can values be passed bet. precompiler exits & Oracle callinterface?
By using the statement EXECIAFGET & EXECIAFPUT.
79. How can I message to passed to the user from reports?
By using SRW.MESSAGE function.
Oracle DBA
1. SNAPSHOT is used for[DBA] a] Synonym, b] Table space, c] System server, d] Dynamic datareplication
Ans : D
2. We can create SNAPSHOTLOG for[DBA] a] Simple snapshots, b] Complex snapshots, c] Both A & B, d]Neither A nor B
Ans : A
3. Transactions per rollback segment is derived from[DBA] a] Db_Block_Buffers, b] Processes, c] Shared_Pool_Size, d] Noneof the above
Ans : B
4. ENQUEUE resources parameter information is derived from[DBA] a] Processes or DDL_LOCKS and DML_LOCKS, b] LOG_BUFFER,c] DB__BLOCK_SIZE..Ans : A
5. LGWR process writes information intoa] Database files, b] Control files, c] Redolog files, d] All theabove.Ans : C
6. SET TRANSACTION USE ROLLBACK SEGMENT is used to create userobjectsin a particular Tablespacea] True, b] FalseAns : False
7. Databases overall structure is maintained in a file calleda] Redolog file, b] Data file, c] Control file, d] All of theabove.Ans : C
8. These following parameters are optional in init.ora parameter fileDB_BLOCK_SIZE,PROCESSESa] True, b] FalseAns : False
9. Constraints cannot be exported through EXPORT commanda] True, b] FalseAns : False
10. It is very difficult to grant and manage common privileges needed bydifferent groups ofdatabase users using the rolesa] True, b] FalseAns : False
11. What is difference between a DIALOG WINDOW and a DOCUMENT WINDOWregardingmoving the window with respect to the application windowa] Both windows behave the same way as far as moving the window isconcerned.b] A document window can be moved outside the application window whilea dialogwindow cannot be movedc] A dialog window can be moved outside the application window while adocumentwindow cannot be movedAns : C
12. What is the difference between a MESSAGEBOX and an ALERTa] A messagebox can be used only by the system and cannot be used inuser applicationwhile an alert can be used in user application also.b] A alert can be used only by the system and cannot be use din userapplicationwhile an messagebox can be used in user application also.c] An alert requires an response from the userwhile a messagebox justflashes a messageand only requires an acknowledment from the userd] An message box requires an response from the userwhile a alert justflashes amessage an only requires an acknowledment from the userAns : C
13. Which of the following is not an reason for the fact that most of theprocessing is done at theserver ?a] To reduce network traffic. b] For application sharing, c] Toimplement business rulescentrally, d] None of the aboveAns : D
14. Can a DIALOG WINDOW have scroll bar attached to it ?a] Yes, b] NoAns : B
15. Which of the following is not an advantage of GUI systems ?a] Intuitive and easy to use., b] GUI's can display multipleapplications in multiple windowsc] GUI's provide more user interface objects for a developerd] None of the aboveAns :D
16. What is the difference between a LIST BOX and a COMBO BOX ?a] In the list box, the user is restricted to selecting a value from alist but in a combo boxthe user can type in a value which is not in the listb] A list box is a data entry area while a combo box can be used onlyfor control purposesc] In a combo box, the user is restricted to selecting a value from alist but in a list box theuser can type in a value which is not in the listd] None of the aboveAns : A
17. In a CLIENT/SERVER environment , which of the following would not bedone at the client ?a] User interface part, b] Data validation at entry line, c]Responding to user events,d] None of the aboveAns : D
18. Why is it better to use an INTEGRITY CONSTRAINT to validate data in atable than to use aSTORED PROCEDURE ?a] Because an integrity constraint is automatically checked while datais inserted into orupdated in a table while a stored procedure has to bespecifically invokedb] Because the stored procedure occupies more space in the databasethan a integrityconstraint definitionc] Because a stored procedure creates more network traffic than aintegrity constraintdefinitionAns : A
19. Which of the following is not an advantage of a client/server model ?a] A client/server model allows centralised control of data andcentralised implementationof business rules.b] A client/server model increases developer;s productivityc] A client/server model is suitable for all applicationsd] None of the above.Ans : C
20. What does DLL stands for ?a] Dynamic Language Libraryb] Dynamic Link Libraryc] Dynamic Load Libraryd] None of the aboveAns : B
21. POST-BLOCK trigger is aa] Navigational triggerb] Key triggerc] Transactional triggerd] None of the aboveAns : A
22. The system variable that records the select statement that SQL * FORMSmost recently usedto populate a block isa] SYSTEM.LAST_RECORDb] SYSTEM.CURSOR_RECORDc] SYSTEM.CURSOR_FIELDd] SYSTEM.LAST_QUERYAns: D
23. Which of the following is TRUE for the ENFORCE KEY fielda] ENFORCE KEY field characterstic indicates the source of the valuethat SQL*FORMSuses to populate the fieldb] A field with the ENFORCE KEY characterstic should have the INPUTALLOWEDcharaterstic turned offa] Only 1 is TRUEb] Only 2 is TRUEc] Both 1 and 2 are TRUEd] Both 1 and 2 are FALSEAns : A
24. What is the maximum size of the page ?a] Characters wide & 265 characters lengthb] Characters wide & 265 characters lengthc] Characters wide & 80 characters lengthd] None of the aboveAns : B
25. A FORM is madeup of which of the following objectsa] block, fields only,b] blocks, fields, pages only,c] blocks, fields, pages, triggers and form level procedures,d] Only blocks.Ans : C
26. For the following statements which is true1] Page is an object owned by a form2] Pages are a collection of display information such as constant textand graphics.a] Only 1 is TRUEb] Only 2 is TRUEc] Both 1 & 2 are TRUEd] Both are FALSEAns : B
27. The packaged procedure that makes data in form permanent in theDatabase isa] Postb] Post formc] Commit formd] None of the aboveAns : C
28. Which of the following is TRUE for the SYSTEM VARIABLE $$date$$a] Can be assigned to a global variableb] Can be assigned to any field only during design timec] Can be assigned to any variable or field during run timed] None of the aboveAns : B
29. Which of the following packaged procedure is UNRESTRICTED ?a] CALL_INPUT, b] CLEAR_BLOCK, c] EXECUTE_QUERY, d] USER_EXITAns : D
30. Identify the RESTRICTED packaged procedure from the followinga] USER_EXIT, b] MESSAGE, c] BREAK, d] EXIT_FORMAns : D
31. What is SQL*FORMSa] SQL*FORMS is a 4GL tool for developing & executing Oracle basedinteractiveapplications.b] SQL*FORMS is a 3GL tool for connecting to the Database.c] SQL*FORMS is a reporting toold] None of the above.Ans : A
32. Name the two files that are created when you generate a form usingForms 3.0a] FMB &amp;amp; FMX, b] FMR & FDX, c] INP & FRM, d] None of the aboveAns : C
33. What is a triggera] A piece of logic written in PL/SQLb] Executed at the arrival of a SQL*FORMS eventc] Both A & Bd] None of the aboveAns : C
34. Which of the folowing is TRUE for a ERASE packaged procedure1] ERASE removes an indicated Global variable & releases the memoryassociated with it2] ERASE is used to remove a field from a page1] Only 1 is TRUE2] Only 2 is TRUE3] Both 1 & 2 are TRUE4] Both 1 & 2 are FALSEAns : 1
35. All datafiles related to a Tablespace are removed when the Tablespaceis droppeda] TRUEb] FALSEAns : B
36. Size of Tablespace can be increased bya] Increasing the size of one of the Datafilesb] Adding one or more Datafilesc] Cannot be increasedd] None of the aboveAns : B
37. Multiple Tablespaces can share a single datafilea] TRUEb] FALSEAns : B
38. A set of Dictionary tables are createda] Once for the Entire Databaseb] Every time a user is createdc] Every time a Tablespace is createdd] None of the aboveAns : A
39. Datadictionary can span across multiple Tablespacesa] TRUEb] FALSEAns : B
40. What is a DATABLOCKa] Set of Extentsb] Set of Segmentsc] Smallest Database storage unitd] None of the aboveAns : C
41. Can an Integrity Constraint be enforced on a table if some existingtable data does not satisfythe constrainta] Yesb] NoAns : B
42. A column defined as PRIMARY KEY can have NULL'sa] TRUEb] FALSEAns : B
43. A Transaction endsa] Only when it is Committedb] Only when it is Rolledbackc] When it is Committed or Rolledbackd] None of the aboveAns : C
44. A Database Procedure is stored in the Databasea] In compiled formb] As source codec] Both A & Bd] Not storedAns : C
45. A database trigger doesnot apply to data loaded before the definitionof the triggera] TRUEb] FALSEAns : A
46. Dedicated server configuration isa] One server process - Many user processesb] Many server processes - One user processc] One server process - One user processd] Many server processes - Many user processesAns : C
47. Which of the following does not affect the size of the SGAa] Database bufferb] Redolog bufferc] Stored procedured] Shared poolAns : C
48. What does a COMMIT statement do to a CURSORa] Open the Cursorb] Fetch the Cursorc] Close the Cursord] None of the aboveAns : D
49. Which of the following is TRUE1] Host variables are declared anywhere in the program2] Host variables are declared in the DECLARE sectiona] Only 1 is TRUEb] Only 2 is TRUEc] Both 1 & 2are TRUEd] Both are FALSEAns : B
50. Which of the following is NOT VALID is PL/SQLa] Bool boolean;b] NUM1, NUM2 number;c] deptname dept.dname%type;d] date1 date := sysdateAns : B
51. Declarefvar number := null; svar number := 5Begingoto <<>>if fvar is null then<<>>svar := svar + 5end if;End;
What will be the value of svar after the execution ?a] Errorb] 10c] 5d] None of the above
Ans : A
52. Which of the following is not correct about an Exception ?a] Raised automatically / Explicitly in response to an ORACLE_ERRORb] An exception will be raised when an error occurs in that blockc] Process terminates after completion of error sequence.d] A Procedure or Sequence of statements may be processed.
Ans : C
53. Which of the following is not correct about User_Defined Exceptions ?a] Must be declaredb] Must be raised explicitlyc] Raised automatically in response to an Oracle errord] None of the above
Ans : C
54. A Stored Procedure is aa] Sequence of SQL or PL/SQL statements to perform specific functionb] Stored in compiled form in the databasec] Can be called from all client environmetsd] All of the above
Ans : D
55. Which of the following statement is falsea] Any procedure can raise an error and return an user message anderror numberb] Error number ranging from 20000 to 20999 are reserved for userdefined messagesc] Oracle checks Uniqueness of User defined errorsd] Raise_Application_error is used for raising an user defined error.
Ans : C
56. Is it possible to open a cursor which is in a Package in anotherprocedure ?a] Yesb] No
Ans : A
57. Is it possible to use Transactional control statements in DatabaseTriggers ?a] Yesb] No
Ans : B
58. Is it possible to Enable or Disable a Database trigger ?a] Yesb] No
Ans : A
59. PL/SQL supports datatype(s)a] Scalar datatypeb] Composite datatypec] All of the aboved] None of the above
Ans C
60. Find the ODD datatype outa] VARCHAR2b] RECORDc] BOOLEANd] RAW
Ans : B
61. Which of the following is not correct about the "TABLE" datatype ?a] Can contain any no of columnsb] Simulates a One-dimensional array of unlimited sizec] Column datatype of any Scalar typed] None of the above
Ans : A
62. Find the ODD one out of the followinga] OPENb] CLOSEc] INSERTd] FETCH
Ans C
63. Which of the following is not correct about Cursor ?a] Cursor is a named Private SQL areab] Cursor holds temporary resultsc] Cursor is used for retrieving multiple rowsd] SQL uses implicit Cursors to retrieve rows
Ans : B
64. Which of the following is NOT VALID in PL/SQL ?a] Select ... intob] Updatec] Created] Delete
Ans : C
65. What is the Result of the following 'VIK'NULL'RAM' ?a] Errorb] VIK RAMc] VIKRAMd] NULL
Ans : C
66. Declarea number := 5; b number := null; c number := 10;Beginif a > b AND a <> ( Select count(*) from Emp E2where E1.SAL > E2.SAL ) will retrievea] 3500,5000,2500b] 5000,2850c] 2850,5750d] 5000,5750
Ans : A
72. Is it possible to modify a Datatype of a column when column containsdata ?a] Yesb] No
Ans B
73. Which of the following is not correct about a View ?a] To protect some of the columns of a table from other usersb] Ocuupies data storage spacec] To hide complexity of a queryd] To hide complexity of a calculations
Ans : B
74. Which is not part of the Data Definiton Language ?a] CREATEb] ALTERc] ALTER SESSION
Ans : C
75. The Data Manipulation Language statements area] INSERTb] UPDATEc] SELECTd] All of the above
Ans : D
76. EMPNO ENAME SALA822 RAMASWAMY 3500A812 NARAYAN 5000A973 UMESHA500 BALAJI 5750
Using the above dataSelect count(sal) from Emp will retrievea] 1b] 0c] 3d] None of the above
Ans : C
77. If an UNIQUE KEY constraint on DATE column is created, will it acceptthe rows that areinserted with SYSDATE ?a] Willb] Won't
Ans : B
78. What are the different events in Triggers ?a] Define, Createb] Drop, Commentc] Insert, Update, Deleted] All of the above
Ans : C79. What built-in subprogram is used to manipulate images in image items ?a] Zoom_outb] Zoom_in'c] Image_zoomd] Zoom_image
Ans : C
80. Can we pass RECORD GROUP between FORMS ?a] Yesb] No
Ans : A
81. SHOW_ALERT function returnsa] Booleanb] Numberc] Characterd] None of the above
Ans : B
82. What SYSTEM VARIABLE is used to refer DATABASE TIME ?a] $$dbtime$$b] $$time$$c] $$datetime$$d] None of the above
Ans : A
83. :SYSTEM.EFFECTIVE.DATE varaible isa] Read onlyb] Read & Writec] Write onlyd] None of the above
Ans : C
84. How can you CALL Reports from Forms4.0 ?a] Run_Report built_inb] Call_Report built_inc] Run_Product built_ind] Call_Product built_in
Ans : C
85. When do you get a .PLL extension ?a] Save Library fileb] Generate Library filec] Run Library filed] None of the above
Ans : A
86. What is built_in Subprogram ?a] Stored procedure & Functionb] Collection of Subprogramc] Collection of Packagesd] None of the above
Ans : D
87. GET_BLOCK property is aa] Restricted procedureb] Unrestricted procedurec] Library functiond] None of the above
Ans : D
88. A CONTROL BLOCK can sometimes refer to a BASETABLE ?a] TRUEb] FALSE
Ans : B
89. What do you mean by CHECK BOX ?a] Two state controlb] One state controlc] Three state controld] none of the above
Ans : C - Please check the Correcness of this Answer ( The correct answeris 2 )
90. List of Values (LOV) supportsa] Single columnb] Multi columnc] Single or Multi columnd] None of the above
Ans : C
91. What is Library in Forms 4.0 ?a] Collection of External fieldb] Collection of built_in packagesc] Collection of PL/SQl functions, procedures and packagesd] Collection of PL/SQL procedures & triggers
Ans : C
92. Can we use a RESTRICTED packaged procedure in WHEN_TEXT_ITEM trigger ?a] Yesb] No
Ans : B
93. Can we use GO_BLOCK package in a PRE_TEXT_ITEM trigger ?a] Yesb] No
Ans : B
94. What type of file is used for porting Forms 4.5 applications to variousplatforms ?a] .FMB fileb] .FMX filec] .FMT filed] .EXE file
Ans : C
95. What built_in procedure is used to get IMAGES in Forms 4.5 ?a] READ_IMAGE_FILEb] GET_IMAGE_FILEc] READ_FILEd] GET_FILE
Ans A
96. When a form is invoked with CALL_FORM does Oracle forms issuesSAVEPOINT ?a] Yesb] No
Ans : A
97. Can we attach the same LOV to different fields in Design time ?a] Yesb] No
Ans : A
98. How do you pass values from one form to another form ?a] LOVb] Parametersc] Local variablesd] None of the above
Ans : B
99. Can you copy the PROGRAM UNIT into an Object group ?a] Yesb] No
Ans : B
100. Can MULTIPLE DOCUMENT INTERFACE (MDI) be used in Forms 4.5 ?a] Yesb] No
Ans : A
101. When is a .FMB file extension is created in Forms 4.5 ?a] Generating formb] Executing formc] Save formd] Run form
Ans : C
102. What is a Built_in subprogram ?a] Libraryb] Stored procedure & Functionc] Collection of Subprogramsd] None of the above
Ans : D
103. What is a RADIO GROUP ?a] Mutually exclusiveb] Select more than one columnc] Above all TRUEd] Above all FALSE
Ans : A
104. Identify the Odd one of the following statements ?a] Poplistb] Tlistc] List of valuesd] Combo box
Ans : C
105. What is an ALERT ?a] Modeless windowb] Modal windowc] Both are TRUEd] None of the above
Ans : B
106. Can an Alert message be changed at runtime ?a] Yesb] No
Ans : A
107. Can we create an LOV without an RECORD GROUP ?a} Yesb] No
Ans : B
108. How many no of columns can a RECORD GROUP have ?a] 10b] 20c] 50d] None of the above
Ans D
109. Oracle precompiler translates the EMBEDDED SQL statemens intoa] Oracle FORMSb] Oracle REPORTSc] Oracle LIBRARYd] None of the above
Ans : D
110. Kind of COMMENT statements placed within SQL statements ?a] Asterisk(*) in column ?b] ANSI SQL style statements(...)c] C-Style comments (/*......*/)d] All the above
Ans : D
111. What is the appropriate destination type to send the output to aprinter ?a] Screenb] Previewerc] Either of the aboved] None of the above
Ans : D
112. What is TERM ?a] TERM is the terminal definition file that describes the terminalfrom which you areusing R20RUN ( Reports run time )b] TERM is the terminal definition file that describes the terminalfrom which you areusing R20DES ( Reports designer )c] There is no Parameter called TERM in Reports 2.0d] None of the above
Ans : A
113. If the maximum records retrieved property of a query is set to 10,then a summary value willbe calculateda] Only for 10 recordsb] For all the records retrievedc] For all therecords in the referenced tabled] None of the above
Ans : A
114. With which function of a summary item in the COMPUTE AT optionrequired ?a] Sumb] Standard deviationc] Varianced] % of Total function
Ans : D
115. For a field in a repeating frame, can the source come from a columnwhich does not exist inthe datagroup which forms the base of the frame ?a] Yesb] No
Ans : A
116. What are the different file extensions that are created by OracleReports ?a] .RDF file & .RPX fileb] .RDX file & .RDF filec] .REP file & .RDF filed] None of the above
Ans : C
117. Is it possible to Disable the Parameter form while running the report?a] Yesb] No
Ans : A
118.What are the SQL clauses supported in the link property sheet ?a] WHERE & START WITHb] WHERE & HAVINGc} START WITH & HAVINGd] WHERE, START WITH & HAVING
Ans : D
119. What are the types of Calculated columns available ?a] Summary, Place holder & Procedure columnb] Summary, Procedure & Formula columnsc] Procedure, Formula & Place holder columnsd] Summary, Formula & Place holder columns
Ans.: D
120. If two groups are not linked in the data model editor, what is thehierarchy between them?a] There is no hierarchy between unlinked groupsb] The group that is right ranks higher than the group that is to theleftc] The group that is above or leftmost ranks higher than the groupthat is to right or belowitd] None of the above
Ans : C
121. Sequence of events takes place while starting a Database isa] Database opened, File mounted, Instance startedb] Instance started, Database mounted & Database openedc] Database opened, Instance started & file mountedd] Files mounted, Instance started & Database opened
Ans : B
122. SYSTEM TABLESPACE can be made off-linea] Yesb] No
Ans : B
123. ENQUEUE_RESOURCES parameter information is derived froma] PROCESS or DDL_LOCKS & DML_LOCKSb] LOG BUFFERc] DB_BLOCK_SIZEd] DB_BLOCK_BUFFERS
Ans : A
124. SMON process is used to write into LOG filesa] TRUEb] FALSE
Ans : B
125. EXP command is useda] To take Backup of the Oracle Databaseb] To import data from the exported dump filec] To create Rollback segmentsd] None of the above
Ans : A
126. SNAPSHOTS cannot be refreshed automaticallya] TRUEb] FALSEAns : B127. The User can set Archive file name formatsa] TRUEb] FALSE
Ans : A
128. The following parameters are optional in init.ora parameter fileDB_BLOCK_SIZE,PROCESSa} TRUEb] FALSE
Ans : B129. NOARCHIEVELOG parameter is used to enable the database in Archievemodea] TRUEb] FALSE
Ans : B
130. Constraints cannot be exported through Export command?a] TRUEb] FALSE
Ans : B
131. It is very difficult to grant and manage common priveleges needed bydifferent groups ofdatabase users using rolesa] TRUEb] FALSE
Ans : B
132. The status of the Rollback segment can be viewed througha] DBA_SEGMENTSb] DBA_ROLESc] DBA_FREE_SPACESd] DBA_ROLLBACK_SEG
Ans : D
133. Explicitly we can assign transaction to a rollback segmenta] TRUEB] FALSE
Ans : A
134. What file is read by ODBC to load drivers ?a] ODBC.INIb] ODBC.DLLc] ODBCDRV.INId] None of the above
Ans : A

What is normalization? - Well a relational database is basically composed of tables that contain related data. So the Process of organizing this data into tables is actually referred to as normalization.
What is a Stored Procedure? - Its nothing but a set of T-SQL statements combined to perform a single task of several tasks. Its basically like a Macro so when you invoke the Stored procedure, you actually run a set of statements.
Can you give an example of Stored Procedure? - sp_helpdb , sp_who2, sp_renamedb are a set of system defined stored procedures. We can also have user defined stored procedures which can be called in similar way.
What is a trigger? - Triggers are basically used to implement business rules. Triggers is also similar to stored procedures. The difference is that it can be activated when data is added or edited or deleted from a table in a database.
What is a view? - If we have several tables in a db and we want to view only specific columns from specific tables we can go for views. It would also suffice the needs of security some times allowing specfic users to see only specific columns based on the permission that we can configure on the view. Views also reduce the effort that is required for writing queries to access specific columns every time.
What is an Index? - When queries are run against a db, an index on that db basically helps in the way the data is sorted to process the query for faster and data retrievals are much faster when we have an index.
What are the types of indexes available with SQL Server? - There are basically two types of indexes that we use with the SQL Server. Clustered and the Non-Clustered.
What is the basic difference between clustered and a non-clustered index? - The difference is that, Clustered index is unique for any given table and we can have only one clustered index on a table. The leaf level of a clustered index is the actual data and the data is resorted in case of clustered index. Whereas in case of non-clustered index the leaf level is actually a pointer to the data in rows so we can have as many non-clustered indexes as we can on the db.
What are cursors? - Well cursors help us to do an operation on a set of data that we retrieve by commands such as Select columns from table. For example : If we have duplicate records in a table we can remove it by declaring a cursor which would check the records during retrieval one by one and remove rows which have duplicate values.
Can you tell me the difference between DELETE & TRUNCATE commands? - Delete command removes the rows from a table based on the condition that we provide with a WHERE clause. Truncate will actually remove all the rows from a table and there will be no data in the table after we run the truncate command.
Can we use Truncate command on a table which is referenced by FOREIGN KEY? - No. We cannot use Truncate command on a table with Foreign Key because of referential integrity.
What is the difference between a HAVING CLAUSE and a WHERE CLAUSE? - Having Clause is basically used only with the GROUP BY function in a query. WHERE Clause is applied to each row before they are part of the GROUP BY function in a query.
What do you mean by COLLATION? - Collation is basically the sort order. There are three types of sort order Dictionary case sensitive, Dictonary - case insensitive and Binary.

2006-05-01T23:51:00.000-07:00

Misllaneous tech links:

1. http://www.tutorialdownloads.com

2006-05-01T23:50:00.000-07:00

Misl information links:
1. http://www.javaranch.com/

C++ Question Links:
1. http://harishds.weblogs.us/archives/011083.html
2. http://www.techinterviews.com/?p=96#comment-25679

Java Question Links:
1. Java Networking: http://www.io.com/~maus/jnetfaq.html
2. Java questions and explainations: http://www.sap-img.com/java/index.htm
3. Java Question Banks: http://www.mantrotech.com/technology/java/javacert_questionbank_1.asp

General Questions Links:
1. http://www.techinterviews.com/?p=238
2. Java forum: http://www.artima.com/forums/forum.jsp?forum=1

C++ Language Tutorials:
1. http://www.cplusplus.com/doc/tutorial/
2. http://www.camtp.uni-mb.si/books/Thinking-in-C++/TIC2Vone-distribution/html/Contents.html

Database Information:
1. DB2 : http://publib.boulder.ibm.com/iseries/v5r2/ic2924/index.htm?info/sqlp/rbafymst02.htm

2006-05-01T22:53:00.000-07:00

Java Questions:

1. What is a transient variable?
A transient variable is a variable that may not be serialized.

2. Which containers use a border Layout as their default layout?
The window, Frame and Dialog classes use a border layout as their default layout.

3. Why do threads block on I/O?
Threads block on I/O (that is enters the waiting state) so that other threads may execute while the I/O Operation is performed.

4. How are Observer and Observable used?
Objects that subclass the Observable class maintain a list of observers. When an Observable object is updated it invokes the update() method of each of its observers to notify the observers that it has changed state. The Observer interface is implemented by objects that observe Observable objects.

5. What is synchronization and why is it important?
With respect to multithreading, synchronization is the capability to control the access of multiple threads to shared resources. Without synchronization, it is possible for one thread to modify a shared object while another thread is in the process of using or updating that object's value. This often leads to significant errors.

6. Can a lock be acquired on a class?
Yes, a lock can be acquired on a class. This lock is acquired on the class's Class object.

7. What's new with the stop(), suspend() and resume() methods in JDK 1.2?
The stop(), suspend() and resume() methods have been deprecated in JDK 1.2.
8. Is null a keyword?
The null value is not a keyword.

9. What is the preferred size of a component?
The preferred size of a component is the minimum component size that will allow the component to display normally.

10. What method is used to specify a container's layout?
The setLayout() method is used to specify a container's layout.

11. Which containers use a FlowLayout as their default layout?
The Panel and Applet classes use the FlowLayout as their default layout.

12. What state does a thread enter when it terminates its processing?
When a thread terminates its processing, it enters the dead state.

13. What is the Collections API?
The Collections API is a set of classes and interfaces that support operations on collections of objects.

14. which characters may be used as the second character of an identifier, but not as the first character of an identifier?
The digits 0 through 9 may not be used as the first character of an identifier but they may be used after the first character of an identifier.
15. What is the List interface?
The List interface provides support for ordered collections of objects.

16. How does Java handle integer overflows and underflows?
It uses those low order bytes of the result that can fit into the size of the type allowed by the operation.

17. What is the Vector class?
The Vector class provides the capability to implement a growable array of objects

18. What modifiers may be used with an inner class that is a member of an outer class?
A (non-local) inner class may be declared as public, protected, private, static, final, or abstract.

19. What is an Iterator interface?
The Iterator interface is used to step through the elements of a Collection.

20. What is the difference between the >> and >>> operators?
The >> operator carries the sign bit when shifting right. The >>> zero-fills bits that have been shifted out.

21. Which method of the Component class is used to set the position and size of a component?
setBounds()
22. How many bits are used to represent Unicode, ASCII, UTF-16, and UTF-8 characters?
Unicode requires 16 bits and ASCII require 7 bits. Although the ASCII character set uses only 7 bits, it is usually represented as 8 bits. UTF-8 represents characters using 8, 16, and 18 bit patterns. UTF-16 uses 16-bit and larger bit patterns.

23 What is the difference between yielding and sleeping?
When a task invokes its yield() method, it returns to the ready state. When a task invokes its sleep() method, it returns to the waiting state.

24. Which java.util classes and interfaces support event handling?
The EventObject class and the EventListener interface support event processing.

25. Is sizeof a keyword?
The sizeof operator is not a keyword.

26. What are wrapper classes?
Wrapper classes are classes that allow primitive types to be accessed as objects.

27. Does garbage collection guarantee that a program will not run out of memory?
Garbage collection does not guarantee that a program will not run out of memory. It is possible for programs to use up memory resources faster than they are garbage collected. It is also possible for programs to create objects that are not subject to garbage collection.

28. What restrictions are placed on the location of a package statement within a source code file?
A package statement must appear as the first line in a source code file (excluding blank lines and comments).
29. Can an object's finalize() method be invoked while it is reachable?
An object's finalize() method cannot be invoked by the garbage collector while the object is still reachable. However, an object's finalize() method may be invoked by other objects.

30. What is the immediate superclass of the Applet class?
Panel

31. What is the difference between preemptive scheduling and time slicing?
Under preemptive scheduling, the highest priority task executes until it enters the waiting or dead states or a higher priority task comes into existence. Under time slicing, a task executes for a predefined slice of time and then reenters the pool of ready tasks. The scheduler then determines which task should execute next, based on priority and other factors.

32. Name three Component subclasses that support painting.
The Canvas, Frame, Panel, and Applet classes support painting.

33. What value does readLine() return when it has reached the end of a file?
The readLine() method returns null when it has reached the end of a file.

34. What is the immediate superclass of the Dialog class?
Window.

35. What is clipping?
Clipping is the process of confining paint operations to a limited area or shape.
36. What is a native method?
A native method is a method that is implemented in a language other than Java.

37. Can a for statement loop indefinitely?
Yes, a for statement can loop indefinitely. For example, consider the following:
for(;;) ;

38. What are order of precedence and associativity, and how are they used?
Order of precedence determines the order in which operators are evaluated in expressions. Associatity determines whether an expression is evaluated left-to-right or right-to-left

39. When a thread blocks on I/O, what state does it enter?
A thread enters the waiting state when it blocks on I/O.

40. To what value is a variable of the String type automatically initialized?
The default value of a String type is null.

41. What is the catch or declare rule for method declarations?
If a checked exception may be thrown within the body of a method, the method must either catch the exception or declare it in its throws clause.

42. What is the difference between a MenuItem and a CheckboxMenuItem?
The CheckboxMenuItem class extends the MenuItem class to support a menu item that may be checked or unchecked.
43. What is a task's priority and how is it used in scheduling?
A task's priority is an integer value that identifies the relative order in which it should be executed with respect to other tasks. The scheduler attempts to schedule higher priority tasks before lower priority tasks.

44. What class is the top of the AWT event hierarchy?
The java.awt.AWTEvent class is the highest-level class in the AWT event-class hierarchy.

45. When a thread is created and started, what is its initial state?
A thread is in the ready state after it has been created and started.

46. Can an anonymous class be declared as implementing an interface and extending a class?
An anonymous class may implement an interface or extend a superclass, but may not be declared to do both.

47. What is the range of the short type?
The range of the short type is -(2^15) to 2^15 - 1.

48. What is the range of the char type?
The range of the char type is 0 to 2^16 - 1.

49. In which package are most of the AWT events that support the event-delegation model defined?
Most of the AWT-related events of the event-delegation model are defined in the java.awt.event package. The AWTEvent class is defined in the java.awt package.
50. What is the immediate superclass of Menu?
MenuItem

51. What is the purpose of finalization?
The purpose of finalization is to give an unreachable object the opportunity to perform any cleanup processing before the object is garbage collected.

52. Which class is the immediate superclass of the MenuComponent class.
Object

53. What invokes a thread's run() method?
After a thread is started, via its start() method or that of the Thread class, the JVM invokes the thread's run() method when the thread is initially executed.

54. What is the difference between the Boolean & operator and the && operator?
If an expression involving the Boolean & operator is evaluated, both operands are evaluated. Then the & operator is applied to the operand. When an expression involving the && operator is evaluated, the first operand is evaluated. If the first operand returns a value of true then the second operand is evaluated. The && operator is then applied to the first and second operands. If the first operand evaluates to false, the evaluation of the second operand is skipped.

55. Name three subclasses of the Component class.
Box.Filler, Button, Canvas, Checkbox, Choice, Container, Label, List, Scrollbar, or TextComponent

56. What is the GregorianCalendar class?
The GregorianCalendar provides support for traditional Western calendars.
57. Which Container method is used to cause a container to be laid out and redisplayed?
validate()

58. What is the purpose of the Runtime class?
The purpose of the Runtime class is to provide access to the Java runtime system.

59. How many times may an object's finalize() method be invoked by the
garbage collector?
An object's finalize() method may only be invoked once by the garbage collector.

60. What is the purpose of the finally clause of a try-catch-finally statement?
The finally clause is used to provide the capability to execute code no matter whether or not an exception is thrown or caught.

61. What is the argument type of a program's main() method?
A program's main() method takes an argument of the String[] type.

62. Which Java operator is right associative?
The = operator is right associative.

63. What is the Locale class?
The Locale class is used to tailor program output to the conventions of a particular geographic, political, or cultural region.64. Can a double value be cast to a byte?
Yes, a double value can be cast to a byte.

65. What is the difference between a break statement and a continue statement?
A break statement results in the termination of the statement to which it applies (switch, for, do, or while). A continue statement is used to end the current loop iteration and return control to the loop statement.

66. What must a class do to implement an interface?
It must provide all of the methods in the interface and identify the interface in its implements clause.

67. What method is invoked to cause an object to begin executing as a separate thread?
The start() method of the Thread class is invoked to cause an object to begin executing as a separate thread.

68. Name two subclasses of the TextComponent class.
TextField and TextArea

69. What is the advantage of the event-delegation model over the earlier event-inheritance model?
The event-delegation model has two advantages over the event-inheritance model. First, it enables event handling to be handled by objects other than the ones that generate the events (or their containers). This allows a clean separation between a component's design and its use. The other advantage of the event-delegation model is that it performs much better in applications where many events are generated. This performance improvement is due to the fact that the event-delegation model does not have to repeatedly process unhandled events, as is the case of the event-inheritance
model.

70. Which containers may have a MenuBar?
Frame
71. How are commas used in the initialization and iteration parts of a for statement?
Commas are used to separate multiple statements within the initialization and iteration parts of a for statement.

72. What is the purpose of the wait(), notify(), and notifyAll() methods?
The wait(),notify(), and notifyAll() methods are used to provide an efficient way for threads to wait for a shared resource. When a thread executes an object's wait() method, it enters the waiting state. It only enters the ready state after another thread invokes the object's notify() or notifyAll() methods.

73. What is an abstract method?
An abstract method is a method whose implementation is deferred to a subclass.

74. How are Java source code files named?
A Java source code file takes the name of a public class or interface that is defined within the file. A source code file may contain at most one public class or interface. If a public class or interface is defined within a source code file, then the source code file must take the name of the public class or interface. If no public class or interface is defined within a source code file, then the file must take on a name that is different than its classes and interfaces. Source code files use the .java extension.

75. What is the relationship between the Canvas class and the Graphics class?
A Canvas object provides access to a Graphics object via its paint() method.

76. What are the high-level thread states?
The high-level thread states are ready, running, waiting, and dead.

77. What value does read() return when it has reached the end of a file?
The read() method returns -1 when it has reached the end of a file.
78. Can a Byte object be cast to a double value?
No, an object cannot be cast to a primitive value.

79. What is the difference between a static and a non-static inner class?
A non-static inner class may have object instances that are associated with instances of the class's outer class. A static inner class does not have any object instances.

80. What is the difference between the String and StringBuffer classes?
String objects are constants. StringBuffer objects are not.

81. If a variable is declared as private, where may the variable be accessed?
A private variable may only be accessed within the class in which it is declared.

82. What is an object's lock and which objects have locks?
An object's lock is a mechanism that is used by multiple threads to obtain synchronized access to the object. A thread may execute a synchronized method of an object only after it has acquired the object's lock. All objects and classes have locks. A class's lock is acquired on the class's Class object.

83. What is the Dictionary class?
The Dictionary class provides the capability to store key-value pairs.

84. How are the elements of a BorderLayout organized?
The elements of a BorderLayout are organized at the borders (North, South, East, and West) and the center of a container.
85. What is the % operator?
It is referred to as the modulo or remainder operator. It returns the remainder of dividing the first operand by the second operand.

86. When can an object reference be cast to an interface reference?
An object reference be cast to an interface reference when the object implements the referenced interface.

87. What is the difference between a Window and a Frame?
The Frame class extends Window to define a main application window that can have a menu bar.

88. Which class is extended by all other classes?
The Object class is extended by all other classes.

89. Can an object be garbage collected while it is still reachable?
A reachable object cannot be garbage collected. Only unreachable objects may be garbage collected..

90. Is the ternary operator written x : y ? z or x ? y : z ?
It is written x ? y : z.

91. What is the difference between the Font and FontMetrics classes?
The FontMetrics class is used to define implementation-specific properties, such as ascent and descent, of a Font object.
92. How is rounding performed under integer division?
The fractional part of the result is truncated. This is known as rounding toward zero.

93. What happens when a thread cannot acquire a lock on an object?
If a thread attempts to execute a synchronized method or synchronized statement and is unable to acquire an object's lock, it enters the waiting state until the lock becomes available.

94. What is the difference between the Reader/Writer class hierarchy and the InputStream/OutputStream class hierarchy?
The Reader/Writer class hierarchy is character-oriented, and the InputStream/OutputStream class hierarchy is byte-oriented.

95. What classes of exceptions may be caught by a catch clause?
A catch clause can catch any exception that may be assigned to the Throwable type. This includes the Error and Exception types.

96. If a class is declared without any access modifiers, where may the class be accessed?
A class that is declared without any access modifiers is said to have package access. This means that the class can only be accessed by other classes and interfaces that are defined within the same package.

97. What is the SimpleTimeZone class?
The SimpleTimeZone class provides support for a Gregorian calendar.

98. What is the Map interface?
The Map interface replaces the JDK 1.1 Dictionary class and is used associate keys with values.99. Does a class inherit the constructors of its superclass?
A class does not inherit constructors from any of its super classes.

100. For which statements does it make sense to use a label?
The only statements for which it makes sense to use a label are those statements that can enclose a break or continue statement.

101. What is the purpose of the System class?
The purpose of the System class is to provide access to system resources.

102. Which TextComponent method is used to set a TextComponent to the read-only state?
setEditable()

103. How are the elements of a CardLayout organized?
The elements of a CardLayout are stacked, one on top of the other, like a deck of cards.

104. Is &amp;amp;amp;amp;amp;&= a valid Java operator?
No, it is not.

105. Name the eight primitive Java types.
The eight primitive types are byte, char, short, int, long, float, double, and boolean.
106. Which class should you use to obtain design information about an object?
The Class class is used to obtain information about an object's design.

107. What is the relationship between clipping and repainting?
When a window is repainted by the AWT painting thread, it sets the clipping regions to the area of the window that requires repainting.

108. Is "abc" a primitive value?
The String literal "abc" is not a primitive value. It is a String object.

109. What is the relationship between an event-listener interface and an event-adapter class?
An event-listener interface defines the methods that must be implemented by an event handler for a particular kind of event. An event adapter provides a default implementation of an event-listener interface.

110. What restrictions are placed on the values of each case of a switch statement?
During compilation, the values of each case of a switch statement must evaluate to a value that can be promoted to an int value.

111. What modifiers may be used with an interface declaration?
An interface may be declared as public or abstract.

112. Is a class a subclass of itself?
A class is a subclass of itself.
113. What is the highest-level event class of the event-delegation model?
The java.util.EventObject class is the highest-level class in the event-delegation class hierarchy.

114. What event results from the clicking of a button?
The ActionEvent event is generated as the result of the clicking of a button.

115. How can a GUI component handle its own events?
A component can handle its own events by implementing the required event-listener interface and adding itself as its own event listener.

116. What is the difference between a while statement and a do statement?
A while statement checks at the beginning of a loop to see whether the next loop iteration should occur. A do statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the body of a loop at least once.

117. How are the elements of a GridBagLayout organized?
The elements of a GridBagLayout are organized according to a grid. However, the elements are of different sizes and may occupy more than one row or column of the grid. In addition, the rows and columns may have different sizes.

118. What advantage do Java's layout managers provide over traditional windowing systems?
Java uses layout managers to lay out components in a consistent manner across all windowing platforms. Since Java's layout managers aren't tied to absolute sizing and positioning, they are able to accommodate platform-specific differences among windowing systems.

119. What is the Collection interface?
The Collection interface provides support for the implementation of a mathematical bag - an unordered collection of objects that may contain duplicates.
120. What modifiers can be used with a local inner class?
A local inner class may be final or abstract.

121. What is the difference between static and non-static variables?
A static variable is associated with the class as a whole rather than with specific instances of a class. Non-static variables take on unique values with each object instance.

122. What is the difference between the paint() and repaint() methods?
The paint() method supports painting via a Graphics object. The repaint() method is used to cause paint() to be invoked by the AWT painting thread.

123. What is the purpose of the File class?
The File class is used to create objects that provide access to the files and directories of a local file system.

124. Can an exception be rethrown?
Yes, an exception can be rethrown.

125. Which Math method is used to calculate the absolute value of a number?
The abs() method is used to calculate absolute values.

126. How does multithreading take place on a computer with a single CPU?
The operating system's task scheduler allocates execution time to multiple tasks. By quickly switching between executing tasks, it creates the impression that tasks execute sequentially.
127. When does the compiler supply a default constructor for a class?
The compiler supplies a default constructor for a class if no other constructors are provided.

128. When is the finally clause of a try-catch-finally statement executed?
The finally clause of the try-catch-finally statement is always executed unless the thread of execution terminates or an exception occurs within the execution of the finally clause.

129. Which class is the immediate superclass of the Container class?
Component

130. If a method is declared as protected, where may the method be accessed?
A protected method may only be accessed by classes or interfaces of the same package or by subclasses of the class in which it is declared.

131. How can the Checkbox class be used to create a radio button?
By associating Checkbox objects with a CheckboxGroup.

132. Which non-Unicode letter characters may be used as the first character of an identifier?
The non-Unicode letter characters $ and _ may appear as the first character of an identifier

133. What restrictions are placed on method overloading?
Two methods may not have the same name and argument list but different return types.
134. What happens when you invoke a thread's interrupt method while it is sleeping or waiting?
When a task's interrupt() method is executed, the task enters the ready state. The next time the task enters the running state, an InterruptedException is thrown.

135. What is casting?
There are two types of casting, casting between primitive numeric types and casting between object references. Casting between numeric types is used to convert larger values, such as double values, to smaller values, such as byte values. Casting between object references is used to refer to an object by a compatible class, interface, or array type reference.

136. What is the return type of a program's main() method?
A program's main() method has a void return type.

137. Name four Container classes.
Window, Frame, Dialog, FileDialog, Panel, Applet, or ScrollPane

138. What is the difference between a Choice and a List?
A Choice is displayed in a compact form that requires you to pull it down to see the list of available choices. Only one item may be selected from a Choice. A List may be displayed in such a way that several List items are visible. A List supports the selection of one or more List items.

139. What class of exceptions are generated by the Java run-time system?
The Java runtime system generates RuntimeException and Error exceptions.

140. What class allows you to read objects directly from a stream?
The ObjectInputStream class supports the reading of objects from input streams.
141. What is the difference between a field variable and a local variable?
A field variable is a variable that is declared as a member of a class. A local variable is a variable that is declared local to a method.

142. Under what conditions is an object's finalize() method invoked by the garbage collector?
The garbage collector invokes an object's finalize() method when it detects that the object has become unreachable.

143. How are this () and super () used with constructors?
this() is used to invoke a constructor of the same class. super() is used to invoke a superclass constructor.

144. What is the relationship between a method's throws clause and the exceptions that can be thrown during the method's execution?
A method's throws clause must declare any checked exceptions that are not caught within the body of the method.

145. What is the difference between the JDK 1.02 event model and the event-delegation model introduced with JDK 1.1?
The JDK 1.02 event model uses an event inheritance or bubbling approach. In this model, components are required to handle their own events. If they do not handle a particular event, the event is inherited by (or bubbled up to) the component's container. The container then either handles the event or it is bubbled up to its container and so on, until the highest-level container has been tried.
In the event-delegation model, specific objects are designated as event handlers for GUI components. These objects implement event-listener interfaces. The event-delegation model is more efficient than the event-inheritance model because it eliminates the processing required to support the bubbling of unhandled events.

146. How is it possible for two String objects with identical values not to be equal under the == operator?
The == operator compares two objects to determine if they are the same object in memory. It is possible for two String objects to have the same value, but located indifferent areas of memory.

147. Why are the methods of the Math class static?
So they can be invoked as if they are a mathematical code library.
148. What Checkbox method allows you to tell if a Checkbox is checked?
getState()

149. What state is a thread in when it is executing?
An executing thread is in the running state.

150. What are the legal operands of the instanceof operator?
The left operand is an object reference or null value and the right operand is a class, interface, or array type.

151. How are the elements of a GridLayout organized?
The elements of a GridBad layout are of equal size and are laid out using the squares of a grid.

152. What an I/O filter?
An I/O filter is an object that reads from one stream and writes to another, usually altering the data in some way as it is passed from one stream to another.

153. If an object is garbage collected, can it become reachable again?
Once an object is garbage collected, it ceases to exist. It can no longer become reachable again.

154. What is the Set interface?
The Set interface provides methods for accessing the elements of a finite mathematical set. Sets do not allow duplicate elements.
155. What classes of exceptions may be thrown by a throw statement?
A throw statement may throw any expression that may be assigned to the Throwable type.

156. What are E and PI?
E is the base of the natural logarithm and PI is mathematical value pi.

157. Are true and false keywords?
The values true and false are not keywords.

158. What is a void return type?
A void return type indicates that a method does not return a value.

159. What is the purpose of the enableEvents() method?
The enableEvents() method is used to enable an event for a particular object. Normally, an event is enabled when a listener is added to an object for a particular event. The enableEvents() method is used by objects that handle events by overriding their event-dispatch methods.

160. What is the difference between the File and RandomAccessFile classes?
The File class encapsulates the files and directories of the local file system. The RandomAccessFile class provides the methods needed to directly access data contained in any part of a file.

161. What happens when you add a double value to a String?
The result is a String object.162. What is your platform's default character encoding?
If you are running Java on English Windows platforms, it is probably Cp1252. If you are running Java on English Solaris platforms, it is most likely 8859_1..

163. Which package is always imported by default?
The java.lang package is always imported by default.

164. What interface must an object implement before it can be written to a stream as an object?
An object must implement the Serializable or Externalizable interface before it can be written to a stream as an object.

165. How are this and super used?
this is used to refer to the current object instance. super is used to refer to the variables and methods of the superclass of the current object instance.

166. What is the purpose of garbage collection?
The purpose of garbage collection is to identify and discard objects that are no longer needed by a program so that their resources may be reclaimed and
reused.

167. What is a compilation unit?
A compilation unit is a Java source code file.

168. What interface is extended by AWT event listeners?
All AWT event listeners extend the java.util.EventListener interface.
169. What restrictions are placed on method overriding?
Overridden methods must have the same name, argument list, and return type.
The overriding method may not limit the access of the method it overrides.
The overriding method may not throw any exceptions that may not be thrown
by the overridden method.

170. How can a dead thread be restarted?
A dead thread cannot be restarted.

171. What happens if an exception is not caught?
An uncaught exception results in the uncaughtException() method of the thread's ThreadGroup being invoked, which eventually results in the termination of the program in which it is thrown.

172. What is a layout manager?
A layout manager is an object that is used to organize components in a container.

173. Which arithmetic operations can result in the throwing of an ArithmeticException?
Integer / and % can result in the throwing of an ArithmeticException.

174. What are three ways in which a thread can enter the waiting state?
A thread can enter the waiting state by invoking its sleep() method, by blocking on I/O, by unsuccessfully attempting to acquire an object's lock, or by invoking an object's wait() method. It can also enter the waiting state by invoking its
(deprecated) suspend() method.

175. Can an abstract class be final?
An abstract class may not be declared as final.176. What is the ResourceBundle class?
The ResourceBundle class is used to store locale-specific resources that can be loaded by a program to tailor the program's appearance to the particular locale in which it is being run.

177. What happens if a try-catch-finally statement does not have a catch clause to handle an exception that is thrown within the body of the try statement?
The exception propagates up to the next higher level try-catch statement (if any) or results in the program's termination.

178. What is numeric promotion?
Numeric promotion is the conversion of a smaller numeric type to a larger numeric type, so that integer and floating-point operations may take place. In numerical promotion, byte, char, and short values are converted to int
values. The int values are also converted to long values, if necessary. The long and float values are converted to double values, as required.

179. What is the difference between a Scrollbar and a ScrollPane?
A Scrollbar is a Component, but not a Container. A ScrollPane is a Container. A ScrollPane handles its own events and performs its own scrolling.

180. What is the difference between a public and a non-public class?
A public class may be accessed outside of its package. A non-public class may not be accessed outside of its package.

181. To what value is a variable of the boolean type automatically initialized?
The default value of the boolean type is false.

182. Can try statements be nested?
Try statements may be tested.
183. What is the difference between the prefix and postfix forms of the ++ operator?
The prefix form performs the increment operation and returns the value of the increment operation. The postfix form returns the current value all of the expression and then performs the increment operation on that value.

184. What is the purpose of a statement block?
A statement block is used to organize a sequence of statements as a single statement group.

185. What is a Java package and how is it used?
A Java package is a naming context for classes and interfaces. A package is used to create a separate name space for groups of classes and interfaces. Packages are also used to organize related classes and interfaces into a single API unit and to control accessibility to these classes and interfaces.

186. What modifiers may be used with a top-level class?
A top-level class may be public, abstract, or final.

187. What are the Object and Class classes used for?
The Object class is the highest-level class in the Java class hierarchy. The Class class is used to represent the classes and interfaces that are loaded by a Java program.

188. How does a try statement determine which catch clause should be used to handle an exception?
When an exception is thrown within the body of a try statement, the catch clauses of the try statement are examined in the order in which they appear. The first catch clause that is capable of handling the exception is executed.
The remaining catch clauses are ignored.

189. Can an unreachable object become reachable again?
An unreachable object may become reachable again. This can happen when the object's finalize() method is invoked and the object performs an operation which causes it to become accessible to reachable objects.190. When is an object subject to garbage collection?
An object is subject to garbage collection when it becomes unreachable to the program in which it is used.

191. What method must be implemented by all threads?
All tasks must implement the run() method, whether they are a subclass of Thread or implement the Runnable interface.

192. What methods are used to get and set the text label displayed by a Button object?
getLabel() and setLabel()

193. Which Component subclass is used for drawing and painting?
Canvas

194. What are synchronized methods and synchronized statements?
Synchronized methods are methods that are used to control access to an object. A thread only executes a synchronized method after it has acquired the lock for the method's object or class. Synchronized statements are similar to synchronized methods. A synchronized statement can only be executed after a thread has acquired the lock for the object or class referenced in the synchronized statement195. What are the two basic ways in which classes that can be run as threads may be defined?
A thread class may be declared as a subclass of Thread, or it may implement the Runnable interface.

196. What are the problems faced by Java programmers who don't use layout managers?
Without layout managers, Java programmers are faced with determining how their GUI will be displayed across multiple windowing systems and finding a common sizing and positioning that will work within the constraints imposed by each windowing system.

197. What is the difference between an if statement and a switch statement?
The if statement is used to select among two alternatives. It uses a boolean expression to decide which alternative should be executed. The switch statement is used to select among multiple alternatives. It uses an int expression to determine which alternative should be executed.

Q 1- What do we call an operator that operates on only one operand? A - An operator that operates on only one operand is called a unary operator.
Q 2- What do we call an operator that operates on two operands? A - An operator that operates on two operands is called a binary operator.
Q 3- Is the minus sign a unary or a binary operator, or both? Explain your answer. A - Both. As a binary operator, the minus sign causes its right operand to be subtracted from its left operand. As a unary operator, the minus sign causes the algebraic sign of the right operand to be changed.
Q 4- Describe operator overloading. A - For those languages that support it (such as C++) operator overloading means that the programmer canredefine the behavior of an operator with respect to objects of a new type defined by that program.
Q5- Java programmers may overload operators: True or False? A 6- False: Unfortunately, Java does not support operator overloading.
Q7 - Show the symbols used for the following operators in Java: assignment, not equal, addition,cast. A - The above listed operators in order are: = != + (type)
Q8 - Is any operator automatically overloaded in Java? If so, identify it and describe its overloadedbehavior. A - The plus sign (+) is automatically overloaded in Java. The plus sign can be used to perform arithmeticaddition. It can also be used to concatenate strings. However, the plus sign does more than concatenate strings. It also performs a conversion to String type. When the plus sign is used to concatenate strings, the operand on the right is automatically converted to a character string before being concatenated with the operand on the left. This assumes that the compiler knows enough about the operand on the right to be able to successfully perform the conversion. It has that knowledge for all of the primitive types and most or all of the built-in reference types.
Q 9- What is the purpose of the cast operator? A - The cast operator is used to purposely convert from one type to another.
Q10 - The increment operator is a binary operator: True or False? A - False: The increment operator is a unary operator.
Q11 - Show the symbol for the increment operator. A - The symbol for the increment operator is two plus signs with nothing between them (++).

Q 12- Describe the appearance and the behavior of the increment operator with both prefix andpostfix notation. Show example, possibly incomplete, code fragments illustrating both notationalforms.
A - The increment operator may be used with both prefix and postfix notation. Basically, the increment operator causes the value of the variable to which it is applied to be increased by one. With prefix notation, the operand appears to the right of the operator ( ++X), while with postfix notation, the operand appears to the left of the operator (X++). The difference in behavior has to do with the point in time that the increment actually occurs if the operator and its operand appear as part of a larger overall expression. With the prefix version, the variable is incremented before it is used to evaluate the larger overall expression. With the postfix version, the variable is used to evaluate the larger overall expression and then it is incremented.
Q13 - Show the output that would be produced by the following Java application.

class prg1
{ //define the controlling class
public static void main(String[] args)
{ //define main methodint x = 5, X = 5, y = 5, Y = 5;
System.out.println("x = " + x );
System.out.println("X = " + X );
System.out.println("x + X++ = " + (x + X++) );
System.out.println("X = " + X );
System.out.println();
System.out.println("y = " + y );
System.out.println("Y = " + Y );
System.out.println("y + ++Y = " + (y + ++Y) );
System.out.println("Y = " + Y );
}
//end main}//End class.

Note no semicolon required//End Java applicationA -

The output from this Java application follows:x = 5X = 5x + X++ = 10X = 6y = 5Y = 5y + ++Y = 11Y = 6

Q 14 - Binary operators use outfix notation: True or False? If your answer is False, explain why.
A - False: Binary operators use infix notation, which means that the operator appears between its operands.
Q15 - In practice, what does it mean to say that an operator that has performed an action returns avalue (or evaluates to a value) of a given type? A - As a result of performing the specified action, an operator can be said to return a value (or evaluate to avalue) of a given type. The type depends on the operator and the type of the operands. To evaluate to a value means that after the action is performed, the operator and its operands are effectively replaced in the expression by the value that is returned.
Q 16 - What are the four categories of operators described in Baldwin's Java tutorial on operators? Doyou agree with this categorization? If not, explain why not. A - Some authors divide Java's operators into the following categories:arithmetic relational and conditional (typically called relational and logical in C++) bitwise and logical assignment
Q17 - Show and describe at least five of the binary arithmetic operators supported by Java(Clarification: binary operators does not mean bitwise operators). A - Java support various arithmetic operators on floating point and integer numbers. The following table lists five of the binary arithmetic operators supported by Java. Operator Description + Adds its operands - Subtracts the right operand from the left operand* Multiplies the operands / Divides the left operand by the right operand % Remainder of dividing the left operand by the right operand
Q18 - In addition to arithmetic addition, what is another use for the plus operator (+)? Show anexample code fragment to illustrate your answer. The code fragment need not be a completestatement. A - The plus operator (+) is also used to concatenate strings : "IMR " + " global Ltd."
Q19 - When the plus operator (+) is used as a concatenation operator, what is the nature of itsbehavior if its right operand is not of type String? If the right operand is a variable that is not of typeString, what is the impact of this behavior on that variable. A - In this case, the operator also coerces the value of the right operand to a string representation for use in the expression only. If the right operand is a variable, the value stored in the variable is not modified in any way.
Q 20- Show and describe four unary arithmetic operators supported by Java. A - Java supports the following four unary arithmetic operators. Operator Description + Indicates a positive value - Negates, or changes algebraic sign ++ Adds one to the operand, both prefix and postfix-- Subtracts one from operand, prefix and postfix
Q20 - What is the type returned by relational operators in Java? A - Relational operators return the boolean type in Java.
Q 21- Show and describe six different relational operators supported by Java. A - Java supports the following set of relational operators: Operator Returns true if > Left operand is greater than right operand >= Left operand is greater than or equal to right operand< operand="=">5 is " + (6>5 ) );}//end main}//End class. Note no semicolon required//End Java applicationA - This program produces the following output: The relational 6<5>5 is true
Q23 - Show and describe three operators (frequently referred to as conditional operators in Java andlogical operators in C++) which are often combined with relational operators to construct morecomplex expressions (often called conditional expressions). Hint: The && operator returns true ifthe left and right operands are both true. What are the other two and how do they behave? A - The following three logical or conditional operators are supported by Java. Operator Typical Use Returns true if &&amp;amp;amp; Left && Right Left and Right are both true Left Right Either Left or Right is true ! ! Right Right is false
Q24 - Describe the special behavior of the operator in the following expression for the case wherethe value of the variable a is less than the value of the variable b. (a <>> OpLeft >> Dist Shift bits of OpLeft right by Dist bits (signed)<<>>> OpLeft >>> Dist Shift bits of OpLeft right by Dist bits (unsigned)& OpLeft & OpRight Bitwise and of the two operands OpLeft OpRight Bitwise inclusive or of the two operands ^ OpLeft ^ OpRight Bitwise exclusive or (xor) of the two operands~ ~ OpRight Bitwise complement of the right operand (unary)
Q28 - In Java, the signed right shift operation populates the vacated bits with the zeros, while the leftshift and the unsigned right shift populate the vacated bits with the sign bit: True or False. If youranswer is False, explain why. A - False: In Java, the signed right shift operation populates the vacated bits with the sign bit, while the left shift and the unsigned right shift populate the vacated bits with zeros.
Q29 - In a signed right-shift operation in Java, the bits shifted off the right end are lost: True or False.If your answer is False, explain why. A - True: For both Java and C++, bits shifted off the right end are lost.
Q30 - Using the symbols 1 and 0 construct a table showing the four possible combinations of 1 and 0.Using a 1 or a 0, show the result of the bitwise and operation on these four combinations of 1 and 0. A - The answer is: 1 and 1 produces 11 and 0 produces 00 and 1 produces 00 and 0 produces 0
Q 31- Using the symbols 1 and 0 construct a truth table showing the four possible combinations of 1and 0. Using a 1 or a 0, show the result of the bitwise inclusive or operation on these fourcombinations on these four combinations of 1 and 0. A - The answer for the inclusive or is: 1 or 1 produces 11 or 0 produces 10 or 1 produces 10 or 0 produces 0
Q 32- Using the symbols 1 and 0 construct a truth table showing the four possible combinations of 1and 0. Using a 1 or a 0, show the result of the bitwise exclusive or operation on these fourcombinations on these four combinations of 1 and 0. A - The answer for the exclusive or is: 1 xor 1 produces 01 xor 0 produces 10 xor 1 produces 10 xor 0 produces 0
Q 33- For the exclusive or, if the two bits are different, the result is a 1. If the two bits are the same,the result is a 0. True or False? If your answer is False, explain why. A - True.
Q 34- Is the assignment operator a unary operator or a binary operator. Select one or the other. A - The assignment operator is a binary operator.
Q 35- In Java, when using the assignment operator, the value stored in memory and represented by theright operand is copied into the memory represented by the left operand: True or False? If youranswer is False, explain why. A - True.
Q 36- Show two of the shortcut assignment operators and explain how they behave by comparingthem with the regular (nonshortcut) versions. Hint: The (^=) operator is a shortcut assignmentoperator. A - Java supports the following list of shortcut assignment operators. These operators allow you to perform an assignment and another operation with a single operator. += -= *= /= %= &= = ^= <<= >>= >>>=For example, the two statements which follow perform the same operation.x += y; x = x + y;The behavior of all the shortcut assignment operators follows this same pattern.
Q 37 - Write a Java application illustrates the difference between the prefix and the postfix versions of the increment operator.
class prog3{static public void main(String[] args){int x = 3;int y = 3;int z = 10;System.out.println("Prefix version gives " + (z + ++x));System.out.println("Postfix version gives " + (z + y++));}//end main}//end class
Q38 Write a Java application that illustrates the use of the following relational operators: < > <= >= == !=class Prog4 { //define the controlling classpublic static void main(String[] args){ //define main methodSystem.out.println("The relational 6<5>5 is " + (6>5 ) );System.out.println("The relational 5>=5 is " + (5>=5 ) );System.out.println("The relational 5<=5 is " + (5<=5 ) );System.out.println("The relational 6==5 is " + (6==5 ) );System.out.println("The relational 6!=5 is " + (6!=5 ) );}//end main}//End prog4 class. Note no semicolon required Q39 - Write a Java application that illustrates the use of the following logical or conditional operators:&& ! class prg5 { //define the controlling classpublic static void main(String[] args){ //define main methodSystem.out.println("true and true is " + (true &&amp;amp;amp; true) );System.out.println("true and false is " + (true && false) ); System.out.println("true or true is " + (true true) );System.out.println("true or false is " + (true false) );System.out.println("false or false is " + (false false) );System.out.println("not true is " + (! true) );System.out.println("not false is " + (! false) ); }//end main} Q40 - Java supports a constant type: True or False. If false, explain why. A - Java does not support a constant type. However, in Java, it is possible to achieve the same result bydeclaring and initializing a variable and making it final. Q41 Provide a code fragment that illustrates the syntax for creating a named constant in Java. A - The syntax for creating a named constant in Java is as follows: final float PI = 3.14159; Q42 - What is the common method of controlling the order of evaluation of expressions in Java? A - you can control the order of evaluation by the use of parentheses. Q43 - What are the three actions normally involved in the operation of a loop (in addition to executingthe code in the body of the loop)? A - The operation of a loop normally involves the following three actions in addition to executing the code in the body of the loop:Initialize a control variable. Test the control variable in a conditional expression. Update the control variable. Q - Java provides two different string classes from which string objects can be instantiated. Whatare they?
A - The two classes are:
String StringBuffer
Q - The StringBuffer class is used for strings that are not allowed to change. The String class isused for strings that are modified by the program: True or False. If false, explain why.
A - False. This statement is backwards. The String class is used for strings that are not allowed to change. TheStringBuffer class is used for strings that are modified by the program.
Q - While the contents of a String object cannot be modified, a reference to a String object can becaused to point to a different String object: True or False. If false, explain why.
A - True.
Q - The use of the new operator is required for instantiation of objects of type String: True orFalse? If false, explain your answer.
A - False. A String object can be instantiated using either of the following statements:
String str1 = new String("String named str2");

String str2 = "String named str1";

Q - The use of the new operator is required for instantiation of objects of type StringBuffer: Trueor False? If false, explain your answer.
A - True.
Q - Provide a code fragment that illustrates how to instantiate an empty StringBuffer object of adefault length and then use a version of the append() method to put some data into the object.
A - See code fragment below:
StringBuffer str5 = new StringBuffer();//accept default initial length
str5.append("StringBuffer named str5");//modify length as needed

Q - Without specifying any explicit numeric values, provide a code fragment that will instantiate anempty StringBuffer object of the correct initial length to contain the string "StringBuffer named str6"and then store that string in the object.
A - See the following code fragment:
StringBuffer str6 = new StringBuffer("StringBuffer named str6".length());
str6.append("StringBuffer named str6");

Q - Provide a code fragment consisting of a single statement showing how to use the Integerwrapper class to convert a string containing digits to an integer and store it in a variable of type int.
A - See code fragment below
int num = new Integer("3625").intValue();

Q - Explain the difference between the capacity() method and the length() methods of theStringBuffer class.
A - The capacity() method returns the amount of space currently allocated for the StringBuffer object. Thelength() method returns the amount of space used.
Q - The following is a valid code fragment: True or False? If false, explain why.
StringBuffer str6 = new StringBuffer("StringBuffer named str6".length());A - True.
Q - Which of the following code fragments is the most efficient, first or second?
String str1 = "THIS STRING IS NAMED str1";String str1 = new String("THIS STRING IS NAMED str1");
A - The first code fragment is the most efficient.
System
Java provides the System class which provides a platform-dependent interface between yourprogram and various system resources: True or False? If false, explain why.
A - False. Java provides the System class which provides a platform-independent interface between yourprogram and those resources.
Q - You must instantiate an object of the System class in order to use it: True or False? If false,explain why.
A - False. You don't need to instantiate an object of the System class to use it, because all of its variables andmethods are class variables and methods.
Q - The following code fragment can be used to instantiate an object of the System class: True orFalse? If false, explain why.
System mySystemObject = new System();

A - False. You cannot instantiate an object of the System class. It is a final class, and all of its constructors areprivate.
Q - What is the purpose of the write() method of the PrintStream class?
A - The write() method is used to write bytes to the stream. You can use write() to write data which is notintended to be interpreted as text (such as bit-mapped graphics data).
Exceptions
Q - The exception-handling capability of Java makes it possible for you to monitor for exceptionalconditions within your program, and to transfer control to special exception-handling code which youdesign. List five keywords that are used for this purpose.
A - try, throw, catch, finally, and throws
Q - All exceptions in Java are thrown by code that you write: True or False? If false, explain why.
A - False. There are situations where an exceptional condition automatically transfers control to specialexception-handling code which you write (cases where you don't provide the code to throw the exception object).
Q - When an exceptional condition causes an exception to be thrown, that exception is an objectderived, either directly, or indirectly from the class Exception: True or False? If false, explain why.
A - False. When an exceptional condition causes an exception to be thrown, that exception is an object derived,either directly, or indirectly from the class Throwable.
Q - All exceptions other than those in the RuntimeException class must be either caught, ordeclared in a throws clause of any method that can throw them: True or False? If false, explainwhy.
A - True.
Q - What method of which class would you use to extract the message from an exception object?
A - The getMessage() method of the Throwable class.
Q - Normally, those exception handlers designed to handle exceptions closest to the root of theexception class hierarchy should be placed first in the list of exception handlers: True or False? Iffalse, explain why.
A - False. The above statement has it backwards. Those handlers designed to handle exceptions furthermost fromthe root of the hierarchy tree should be placed first in the list of exception handlers.
Q - Explain why you should place exception handlers furthermost from the root of the exceptionhierarchy tree first in the list of exception handlers.
A - An exception hander designed to handle a specialized "leaf" object may be preempted by another handlerwhose exception object type is closer to the root of the exception hierarchy tree if the second exception handlerappears earlier in the list of exception handlers.
Q - In addition to writing handlers for very specialized exception objects, the Java language allowsyou to write general exception handlers that handle multiple types of exceptions: True or False? Iffalse, explain why.
A - True.
Q - Your exception handler can be written to handle any class that inherits from Throwable. If youwrite a handler for a node class (a class with no subclasses), you've written a specialized handler: itwill only handle exceptions of that specific type. If you write a handler for a leaf class (a class withsubclasses), you've written a general handler: it will handle any exception whose type is the nodeclass or any of its subclasses. True or False? If false, explain why.
A - False. "Leaf" and "node" are reversed in the above statement. If you write a handler for a "leaf" class (a classwith no subclasses), you've written a specialized handler: it will only handle exceptions of that specific type. Ifyou write a handler for a "node" class (a class with subclasses), you've written a general handler: it will handleany exception whose type is the node class or any of its subclasses."
Q - Java's finally block provides a mechanism that allows your method to clean up after itselfregardless of what happens within the try block. True or False? If false, explain why.
A - True.
Q - Explain how you would specify that a method throws one or more exceptions.
A - To specify that a method throws one or more exceptions, you add a throws clause to the method signature forthe method. The throws clause is composed of the throws keyword followed by a comma-separated list of all theexceptions thrown by that method.
Q - Provide a code fragment that illustrates how you would specify that a method throws more thanone exception.
A - See code fragment below.
void myMethod() throws InterruptedException, MyException,
HerException, UrException
{
//method body
}

Q - What type of argument is required by the throw statement?
A - The throw statement requires a single argument, which must be an object derived either directly or indirectlyfrom the class Throwable.
Q - Some exception objects are automatically thrown by the system. It is also possible for you todefine your own exception classes, and to cause objects of those classes to be thrown whenever anexception occurs. True or False? If false, explain why.
A - True.

=======
Threads
Q - What is the definition of multi-threaded programming according to Patrick Naughton?
A - According to The Java Handbook, by Patrick Naughton,
"Multi-threaded programming is a conceptual paradigm for programming where you divide programs into two or more processes which can be run in parallel."
Q - Multithreading refers to two or more programs executing, "apparently" concurrently, undercontrol of the operating system. The programs need have no relationship with each other, other thanthe fact that you want to start and run them all concurrently. True or False? If false, explain why.
A - False. That is a description of multiprocessing, not multithreading. Multithreading refers to two or moretasks executing, "apparently" concurrently, within a single program.
Q - According to current terminology, the term blocked means that the thread is waiting forsomething to happen and is not consuming computer resources. True or False? If false, explain why.
A - True.
Q - What are the two ways to create threaded programs in Java?
A - In Java, there are two ways to create threaded programs:
Implement the Runnable interface Extend the Thread class
Q - What two steps are required to spawn a thread in Java?
A - The two steps necessary to spawn a thread in Java are:
instantiate an object of type Thread and invoke its run() method.
Q - How do you start a thread actually running in Java?
A - Invoke the start() method on object of the Thread class or of a subclass of the Thread class.
Q - It is always possible to extend the Thread class in your Java applications and applets. True orFalse? If false, explain why.
A - False. Sometimes it is not possible to extend the Thread class, because you must extend some other class and Java does not support multiple inheritance.
Q - Although multithreaded programming in Java is possible, it is also possible to write Javaprograms that do not involve threads: True or False? If false, explain why.
A - False. The main method itself runs in a thread which is started by the interpreter.
Q - What is the name of the method that can be used to determine if a thread is alive?
A - The name of the method is isAlive().
Q - Once you start two or more threads running, unless you specify otherwise, they runsynchronously and independently of one another: True or False? If false, explain why.
A - False. Once you start two or more threads running, unless you specify otherwise, they run asynchronouslyand independently of one another.
Q - The process of keeping one thread from corrupting the data while it is being processed byanother thread is known as synchronization: True or False? If false, explain why.
A - True.
Q - Java allows you to specify the absolute priority of each thread: True or False? If false, explainwhy.
A - False. Java allows you to specify the priority of each thread relative to other threads but not on an absolute basis.
Q - Thread synchronization can be achieved using wait(), notify(), and notifyAll() which aremethods of the Thread class: True or False? If false, explain why.
A - False. wait(), notify(), and notifyAll() are not methods of the Thread class, but rather are methods of theObject class.
Q - When you implement a threaded program, you will always override the _____________method of the Thread class and build the functionality of your threaded program into that method.What is the name of the method?
A - The run() method.
Q - In a multithreaded program, you will start a thread running by invoking the __________ methodon your Thread object which will in turn invoke the ___________ method. What are the names ofthe missing methods, and what are the required parameters for each method?
A - In a multithreaded program, you will start a thread running by invoking the start() method on your Thread object which will in turn invoke the run() method. Neither method takes any parameters.
Q - What do Campione and Walrath list as the four possible states of a thread?
A - New Thread Runnable Not Runnable Dead
Q - What methods can be invoked on a thread object which is in the state that Campione andWalrath refer to as a New Thread and what will happen if you invoke any other method on thethread?
A - When a thread is in this state, you can only start the thread or stop it. Calling any method other than start()or stop() will cause an IllegalThreadStateException.
Q - What, according to Campione and Walrath, will cause a thread to become Not Runnable?
A - a thread becomes Not Runnable when one of the following four events occurs:
Someone invokes its sleep() method. Someone invokes its suspend() method. The thread uses its wait() method to wait on a condition variable. The thread is blocking on I/O.
Q1 - Three keywords are used in Java to specify access control. What are they? A - The three keywords used to specify access control in Java are public, private, and protected.
Q2 - In Java, special access privileges are afforded to other members of the same package: True orFalse? If false, explain your answer. A - True. In Java, special access privileges are afforded to other members of the same package.
Q3 - In Java, class variables are often used with the __________ keyword to create variables thatact like constants.
A - The final keyword.
Q4 - In Java, the ___________ keyword is used to declare a class variable.
A - The static keyword.
Q5 - In Java, the ___________ keyword is used to declare a class method.
A - The static keyword.
Q6 - When you include a method in a Java class definition without use of static keyword, this willresult in objects of that class containing an instance method: True or False? If false, explain why.
A 7- True.
Q8 - Normally each object contains its own copy of each instance method: True or False?
A - False, multiple copies of the method do not normally exist in memory.
Q9- When you invoke an instance method using a specific object, if that method refers to instancevariables of the class, that method is caused to refer to the specific instance variables of the specificobject for which it was invoked: True or False? If false, explain why.
A - True.
Q10 - Instance methods are invoked in Java using the name of the object, the colon, and the name ofthe method as shown below: True or False? If false, explain why.
myObject:myInstanceMethod( )
A - False. Use the period or dot operator, not the colon.
Q11 - Instance methods have access to both instance variables and class variables in Java: True orFalse. If false, explain why.
A - True.
Q12 - Class methods have access to both instance variables and class variables in Java: True orFalse. If false, explain why.
A - False. Class method can only access other class members.
Q13 - What are the two most significant characteristics of class methods?
A - 1. Class methods can only access other class members. 2. Class methods can be accessed using only thename of the class. An object of the class is not required to access class methods.
Q14 - In Java, a class method can be invoked using the name of the class, the colon, and the name ofthe method as shown below: True or False? If false, explain why.
MyClass:myClassMethod()
A - False. You must use the period or dot operator, not the colon.
Q15 - What is meant by overloaded methods?
A - The term overloaded methods means that two or more methods may have the same name so long as theyhave different argument lists.
Q16 - If you overload a method name, the compiler determines at run time, on the basis of thearguments provided to the invocation of the method, which version of the method to call in thatinstance: True or False? If false, explain why.
A - False. The determination is made at compile time.
Q16 - A constructor is a special method which is used to construct an object. A constructor alwayshas the same name as the class in which it is defined, and has no return type specified. True orFalse? If false, explain why.
A - True.
Q17 - Constructors may be overloaded, so a single class may have more than one constructor, all ofwhich have the same name, but different argument lists: True or False. If false, explain why.
A - True
Q18 - What is the purpose of a parameterized constructor?
A - The purpose of a parameterized constructor is to initialize the instance variables of an object when the object is instantiated.
Q 19 - The same set of instance variables can often be initialized in more than one way usingoverloaded constructors: True or False? If false, explain why.
A - True.
Q20 - It is not necessary to provide a constructor in Java. True or False? If false, explain why.
A - True. .
Q 21 You can think of the default constructor as a constructor which doesn't take any parameters:True or False? If false, explain why.
A - True.
Q 22- In Java, if you provide any constructors, the default constructor is no longer providedautomatically: True or False? If false, explain why.
A - True.
Q 23- In Java, if you need both a parameterized constructor and a constructor which doesn't takeparameters (often called a default constructor), you must provide them both: True or False? If false,explain why.
A - True.
Q 24- In Java, you can instantiate objects in static memory at compile time, or you can use the newoperator to request memory from the operating system at runtime and use the constructor toinstantiate the object in that memory: True or False? If false, explain why.
A - False. In Java, objects can only be instantiated on the heap at runtime.
Q25 - Provide a code fragment consisting of a single statement that illustrates how the constructor istypically used in Java to declare, instantiate, and initialize an object. Assume a parameterizedconstructor with three parameters of type int.
A - MyClass myObject = new MyClass(1,2,3);
Q26 - Provide a code fragment consisting of a single statement that illustrates how the defaultconstructor is typically used in Java to declare and instantiate an object.
A - MyClass myObject = new MyClass();
Q 27- What are the three actions performed by the following statement?
MyClass myObject = new MyClass(1,2,3);
A - This statement performs three actions in one.
The object is declared by notifying the compiler of the name of the object. The object is instantiated by using the new operator to allocate memory space to contain the new object. The object is initialized by making a call to the constructor named MyClass.
Q 28- In Java, if you attempt to instantiate an object and the Java Virtual Machine cannot allocate therequisite memory, the system will: ________________________________________.
A - Throw an OutOfMemoryError.
Q 29- The following is a valid method call: True or False. If false, explain why.
obj.myFunction(new myClassConstructor(1,2,3) );//Java version
A - True.
Q30 - In Java, when a method begins execution, all of the parameters are created as local automaticvariables: True or False? If false, explain why.
A - True.
Q31 - In the following statement, an object is instantiated and initialized and passed as a parameter to afunction. What will happen to that object when the function terminates?
obj.myFunction(new myClassConstructor(1,2,3) );//Java version
A - It will become eligible for garbage collection.
Q 32- In Java, you declare and implement a constructor just like you would implement any othermethod in your class, except that: _______________________________________________
A - you do not specify a return type and must not include a return statement.
Q33 - The name of the constructor must be the same as the name of the ___________________.
A - class.
Q 34- Usually in cases of inheritance, you will want the subclass to cause the constructor for thesuperclass to execute last to initialize those instance variables which derive from the superclass:True or False? If false, explain why.
A - False. You will want the subclass to cause the constructor for the superclass to execute first.
Q 35- Provide a code fragment that you would include at the beginning of your constructor for asubclass to cause the constructor for the superclass to be invoked prior to the execution of the bodyof the constructor.
A - super(optional parameters);
Q 36- Every object has a finalize method which is inherited from the class named ________________.
A - object.
Q 37- Before an object is reclaimed by the garbage collector, the _______________ method for theobject is called.
A - finalize
Q 38- In Java, the destructor is always called when an object goes out of scope: True or False? Iffalse, explain why.
A - False. Java does not support the concept of a destructor.
=====
Q 39- The class at the top of the inheritance hierarchy is the Object class and this class is defined in thepackage named java.Object: True or False? If false, explain why.
A - False. The Object class is defined in the package named java.lang.
Q40 - We say that an object has state and behavior: True or False? If false, explain why.
A - True.
Q 41- In Java, a method can be defined as an empty method, normally indicating that it is intended tobe overridden: True or False? If false, explain why.
A - True.
Q 42- Including an empty method in a class definition will make it impossible to instantiate an object ofthat class: True or False.
A - False.
Q 43- A subclass can invoke the constructor for the immediate superclass by causing the last line of ofthe subclass constructor to contain the keyword super followed by a parameter list as though callinga function named super() and the parameter list must match the method signature of the superclassconstructor: True or False? If false, explain why.
A - False. This can only be accomplished by causing the first line of the constructor to contain the keywordsuper followed by a parameter list as though calling a function named super(). The parameter list must match the method signature of the superclass constructor.
Q 43 The equals() method is used to determine if two reference variables point to the same object:True or False? If false, explain why.
A- False. You can use the equals() method to compare two objects for equality. You can use the equality operator (==) to determine if two reference variables point to the same object.
Q 44- The equals() method is used to determine if two separate objects are of the same type andcontain the same data. The method returns false if the objects are equal and true otherwise. Trueor False? If false, explain why.
A - False. The method returns true if the objects are equal and false otherwise.
Q 45 - The equals() method is defined in the Object class: True or False? If false, explain why.
A - True.
Q 46- Your classes can override the equals() method to make an appropriate comparison betweentwo objects of a type that you define: True or False? If false, explain why.
A - True.
Q 47- You must override the equals() method to determine if two string objects contain the same data:True or False? If false, explain why.
A - False. The system already knows how to apply the equals() method to all of the standard classes and objects of which the compiler has knowledge. For example, you can already use the method to test two String objects or two array objects for equality.
Q 48- Given an object named obj1, provide a code fragment that shows how to obtain the name of theclass from which obj1 was instantiated and the name of the superclass of that class.
A - See code fragment below:
System.out.println("Name of class for obj1: " + obj1.getClass().getName());
System.out.println("Name of superclass for obj1: " + obj1.getClass().getSuperclass());
Q 49- Given an object named obj2, provide a code fragment that shows how to use thenewInstance() method to create a new object of the same type
A - See code fragment below:
obj2 = obj1.getClass().newInstance();
Q 50- By overriding the getClass() method, you can use that method to determine the name of theclass from which an object was instantiated: True or False? If false, explain why.
A - False. The getClass() method is a final method and cannot be overridden.
Q 51- You must use the new operator to instantiate an object of type Class: True or False? If false,explain why.
A - False. There is no public constructor for the class Class. Class objects are constructed automatically by theJava Virtual Machine as classes are loaded and or by calls to the defineClass method in the class loader.
Q 52- The Class class provides a toString() method which can be used to convert all objects knownto the compiler to some appropriate string representation. The actual string representation dependson the type of object: True or False? If false, explain why.
A - False. The Object class (not the Class class) provides a toString() method which can be used to convert all objects known to the compiler to some appropriate string representation. The actual string representationdepends on the type of object.
Q 53- You can override the toString() method of the Class class to cause it to convert objects ofyour design to strings: True or False? If false, explain why.
A - False. The toString() method is a method of the Object class, not the Class class.
Q 54- By default, all classes in Java are either direct or indirect descendants of the Class class which isat the top of the inheritance hierarchy: True or False? If false, explain why.
A - False. By default, all classes in Java are either direct or indirect descendants of the Object class (not the Class class) which is at the top of the inheritance hierarchy.
=====
Q 55 - To a limited extent, the interface concept allows you to treat a number of objects, instantiatedfrom different classes, as if they were all of the same type: True or False? If false, explain why.
A - True.
Q 56- At its simplest level, an interface definition has a name, and declares one or more methods:True or False? If false, explain why.
A - True.
Q57- In an interface definition, both the method signatures and the actual implementations (bodies) ofthe methods are provided: True or False? If false, explain why.
A - False. Only the method signatures are provided. The actual implementations (bodies) of the methods are not provided.
Q 58- An interface definition can contain only method declarations: True or False? If false, explainwhy.
A - False. In addition to method declarations, an interface can also declare constants. Nothing else may beincluded inside the body of an interface definition.
Q59 - If classes P, D, and Q all implement interface X, a reference variable for an object of class P,D, or Q could be assigned to a reference variable of type X: True or False? If false, explain why.
A - True.
Q 60- If classes P, D, and Q all implement interface X, then all of the methods declared in X must beexactly the same in classes P, D, and Q: True or False? If false, explain why.
A - False. The interface simply declares the signatures for methods. Classes that implement the interface are free to provide a body for those methods which best suits the needs of the class.
Q 61- If classes P, D, and Q all implement interface X a reference variable for an object of class P,D, or Q could be assigned to a reference variable of type X and that reference variable could beused to access all of the methods of the class (which are not excluded using public, private, orprotected): True or False? If false, explain why.
A - False. If one or more of the classes P, D, and Q, define instance methods which are not declared in theinterface X, then a variable of type X cannot be used to access those instance methods. Those methods can only be accessed using a reference variable of the class in which the method is defined. Reference variables of the type X can only be used to access methods declared in the interface X (or one of its superinterfaces).
Q 61 - The new operator must be used to instantiate an object which is of the type of an interface: Trueor False? If false, explain why.
A - False. Even though you can consider the interface name as a type for purposes of storing references toobjects, you cannot instantiate an object of the interface type itself.
Q 63- One of the difficulties of implementing interfaces is the requirement to coordinate the definition ofinterface methods among the classes that implement the interface: True or False? If false, explainwhy.
A - False. In defining interface methods, each class defines the methods in a manner that is appropriate to its ownclass without concern for how it is defined in other classes.
Q 64- As with classes, multiple interface definitions can be combined into the same source file: True orFalse? If false, explain why.
A- False. The compiler requires interface definitions to be in separate files.
Q 65- List four ways in which interfaces are useful:
A - See the following list:
To a limited extent, the interface concept allows you to treat a number of objects, instantiated fromdifferent classes, as if they were all of the same type Capturing similarities between unrelated classes without forcing a class relationship Declaring methods that one or more classes are expected to implement Revealing an object's programming interface without revealing its class (objects such as these are calledanonymous objects and can be useful when shipping a package of classes to other developers)
Q 66- A minimum interface declaration contains the Java keyword interface, the name of theinterface, and the name of the interface that it extends: True or False? If false, explain why.
A - False. A minimum interface declaration contains the Java keyword interface and the name of the interface. There is no requirement to specify the name of the interface that it extends, because it may not extend another interface.
Q 67 - An interface can extend any number of other interfaces: True or False? If false, explain why.
A - True.
Q 68- Just like a class definition can extend any number of other classes, an interface can extend anynumber of other interfaces: True or False? If false, explain why.
A - False. A class can extend only one other class.
Q 69- An interface can extend any number of other interfaces but not more than one class: True orFalse? If false, explain why.
A - False. An interface cannot extend a class.
Q 70- An interface inherits all constants and methods from its superinterface: True or False? If false,explain why.
A - False. See reasons below:
An interface inherits all constants and methods from its superinterface unless:
the interface hides a constant with another of the same name, or redeclares a method with a new method declaration.
Q 71- The method declaration in an interface consists of the method signature followed by a pair ofempty curly braces: True or False? If false, explain why.
A - False. The method declaration is terminated by a semicolon and no body (no curly braces) is provided for the method.
Q 72- The keyword private is used to restrict access to the members of an interface only to classeswithin the same package: True or False? If false, explain why.
A - False. You may not use private in a member declaration in an interface.
Q 73- All methods declared in an interface are implicitly public and abstract: True or False? If false,explain why.
A - True.
Q 74- In addition to declaring methods, the body of the interface may also define constants. Constantvalues defined in an interface are implicitly public, static, and final: True or False? If false, explainwhy.
A - True.
Q 75- You use an interface by defining a class that extends the interface by name: True or False? Iffalse, explain why.
A - False. You use an interface by defining a class that implements (not extends) the interface by name.
Q 76- When a class claims to implement an interface, it must provide a full definition for all themethods declared in the interface as well as all of the methods declared in all of the superinterfacesof that interface: True or False? If false, explain why.
A - True.
Q 77- A class can implement more than one interface by including several interface names in acomma-separated list of interface names, and by providing a full definition for all of the methodsdeclared in all of the interfaces listed as well as all of the superinterfaces of those interfaces: True orFalse? If false, explain why.
A - True.
Q 78- Whenever a class implements an interface, it is allowed to define only those methods declared inthe interface: True or False? If false, explain why.
A - False. Whenever a class implements an interface, the class must define all of the methods declared in the interface, but is also free to define other methods as well.
Q 79- The definition of an interface is a definition of a new reference data type. You can use interfacenames just about anywhere that you would use other type names, except that you cannot____________________.
A - You cannot instantiate objects of the interface type.
Q 80- Explain in your own words the "bottom line" benefits of the use of an interface.
A - The interface makes it possible for a method in one class to invoke methods on objects of other classes,without the requirement to know the true class of those objects, provided that those objects are all instantiated from classes that implement one or more specified interfaces. In other words, objects of classes that implement specified interfaces can be passed into methods of other objects as the generic type Object, and the methods of the other objects can invoke methods on the incoming objects by first casting them as the interface type.
Q - The Java read() method reads and returns a single byte from the standard input device. Itstores that byte according to what type. What does the method return if the user enters an eof?
A - The Java read() method reads and returns a single byte from the standard input device and stores that bytein an integer. It returns an integer value of -1 if the user enters an eof.
Q - What keystroke combination can be used to simulate an eof at the keyboard of a DOS system?
A - An eof can be simulated on a DOS system keyboard by holding down the ctrl key and pressing the z key.
Q - Provide a Java code fragment illustrating how you would read a stream of bytes from thestandard input device until encountering an eof and quit reading when the eof is encountered.
A - The following Java code fragment will read a stream of bytes from the standard input device untilencountering an eof.
while(System.in.read() != -1) { //do something }
This code fragment accesses the read()method of the object referred to by the class variable named in of theclass named System.
Q - Provide a Java code fragment illustrating two different ways to display a String argument on theJava standard output device. Explain how your code works in object-oriented terms. Make certainthat you explain the difference between the two.
A - The following two code fragments will each display a string argument on the Java standard output device.System.out.println("String argument")
System.out.print("String argument")
In the first case, the code fragment accesses the println() method of the object referred to by the class variablenamed out of the class named System. In the second case, the print() method is accessed instead of the println() method.
The difference between the two is that the println() method automatically inserts a newlineat the end of thestring argument whereas the print() method leaves the display cursor at the end of the string argument. ===============OOP
Q - In Object-Oriented Programming, an object is often said to be an ____________ of a class.
A - An object is often said to be an instance of a class.
Q - In Object-Oriented Programming, an object is often said to have s_______ and b_______.Provide the missing words which begin with the letters shown.
A - In OOP, an object is often said to have state and behavior.
Q - An object's state is contained in its ________ and its behavior is implemented through its________. A - An object's state is contained in its member variables ( or data members) and its behavior is implemented through its methods ( or member functions).
Q - The member variables of an object can be either ____________ or _________ .
A - Its member variables can be either instance variables or class variables.
Q - What is generally meant by the terminology "sending a message to an object?"
A - We activate the behavior of an object by invoking one of its methods (sending it a message).
Q - What are the two things that can usually happen when an object receives a message?
A - When an object receives a message, it usually either performs an action, or modifies its state, or both.
Q - What happens to the memory occupied by an object in Java when the object is no longerneeded, and what do we normally do to make that happen?
A - When an object is no longer needed in Java, we simply forget it. Eventually, the garbage collector may (or may not) come by and pick it up for recycling.
Q - Identify as the stages of an object's life?
A - The stages of an Object's life are:
Creation Use Cleanup
Q - The creation of an object involves three steps (which are often combined). What are the three steps?
A - The three steps are:
declaration (providing a name for the object) instantiation (setting aside memory for the object) optional initialization (providing initial values for the object's instance variables)
Q - Java allows the instantiation of variables of primitive types in dynamic memory: True or False?If false, explain why and what you might be able to do to achieve almost the same result.
A - False. Java does not allow the instantiation of primitive variables in dynamic memory. (However, there are wrapper classes for primitive types which can be used to turn them into objects for this purpose.)
Q - An array of objects in Java is instantiated as an array of reference variables where eachreference variable can then be used to instantiate an object pointed to by the reference variable:True or False. If false, explain why and either provide a code fragment that illustrates your answer
A - True.
Q - In Java, it is always necessary to declare (give a name to) all new objects: True or False? Iffalse, explain why and either provide a code fragment that illustrates your answer
A - It is not always necessary in Java to declare an object (to give it a name). Consider, for example a case where anew object is instantiated to be used in an expression and there is no requirement to be able to access that object outside of the expression.
Q - Instance variables and instance methods can be accessed using an object as the accessmechanism. What is the difference in the syntax used to access an instance variable and aninstance method.
A - None. There is essentially no difference in the syntax used to access a variable or a method.
Q - Once you have instantiated an object, it is always possible to access all of the instancevariables and instance methods of that object by joining the name of the object to the name of thevariable or method using a period: True or False? If false, explain why.
A - False. Sometimes variables or methods may be hidden so as to make it impossible to access them. It is very common to hide the variables and to provide methods which can be accessed to serve as a pathway to the variables.
Q - Given an object named obj that has a public instance method named myMethod(), provide acode fragment that shows the proper syntax for accessing the method.
A - The proper syntax for accessing an instance method named myMethod() follows:
obj.myMethod()
Q - The object-oriented approach normally recommends hiding instance variables behind accessmethods: True or False? If true, explain why.
A - True. The object-oriented approach normally recommends hiding instance variables behind access methods. There are a variety of reasons why. One important reason is that hiding the instance variables makes it possible to later modify the implementation of instance variables to improve the behavior of objects of the class, without a requirement for modifying code that uses the clsss, provided that the access methods are not modified.
Q - The returning of memory (to the operating system) occupied by objects that are no longerneeded is automatically accomplished in Java by a feature commonly known as the____________________. A - The returning of memory to the operating system is taken care of automatically by a feature of Java known as the garbage collector.
Q - All necessary cleanup in a Java program is performed automatically by the garbage collector:True or False? If false, explain why.
A - False. Java does not support anything like a destructor that is guaranteed to be called whenever the object is no longer needed. Therefore, other than returning allocated memory, it is the responsibility of the programmer to explicitly perform any other required cleanup at the appropriate point in time.
Q - When does an object become eligible for garbage collection?
A - An object becomes eligible for garbage collection when there are no more references to that object.
Q - What can your program do to purposely make an object eligible for garbage collection.
A - Your program can make an object eligible for garbage collection by assigning null to all references to the object.
Q - The purpose of garbage collection in Java is to perform all necessary cleanup and the memoryoccupied by objects that are no longer needed will always be reclaimed by the garbage collector:True or False? If false, explain why.
A - False. The sole purpose of garbage collection is to reclaim memory occupied by objects that are no longer needed, and it has no other purpose relative to necessary cleanup. An object becomes eligible for garbage collection when there are no more references to that object. However, just because an object is eligible for garbage collection doesn't mean that it will be reclaimed. The garbage collector runs in a low-priority thread, and may not run at all unless a memory shortage is detected.
Q - Before the garbage collector reclaims the memory occupied by an object, it always calls theobject's _________ method. (Provide the name of the method.) Explain why this method is one ofthe methods in all new classes that you define.
A - Before the garbage collector reclaims the memory occupied by an object, it calls the object's finalizemethod. The finalize method is a member of the Object class. Since all classes inherit from the Object class, your classes also contain the default finalize method.
Q - What must you do to make effective use of the finalize method? Explain why you might want todo this.
A - In order to make use of the finalize method, you must override it, providing the code that you want to have executed before the memory is reclaimed.
Q - You can always be confident that the finalize method will be promptly executed to performnecessary cleanup in a Java program when an object becomes eligible for garbage collection: Trueor False? If false, explain why.
A - False. Although you can be confident that the finalize method will be called before the garbage collector reclaims the memory occupied by a particular object, you cannot be certain when, or if that memory will be reclaimed. There is no guarantee that the memory will be reclaimed by the garbage collector during the execution of your program.
Q - Provide a code fragment illustrating the method call that you can make to ask the garbagecollector to run. This guarantees that garbage collection will take place: True or False? If false,explain why.
A - False. Campione and Walrath indicate that you can ask the garbage collector to run at any time by calling the method shown below. They further point out, however, that making the request does not guarantee that your objects will be reclaimed through garbage collection. System.gc();

2006-05-01T22:51:00.000-07:00

C/C++ Programming Questions:

1. Write a function revstr() - which reverses the given string in the same string buffer using pointers. (ie) Should not use extra buffers for copying the reverse string.

#include

char *rev_str(char *str)
{
char *s = str, *e = s + strlen(s) -1;
char *t = "junk"; /* to be safe - conforming with ANSI C std */

while (s < t =" *e;" len =" strlen(str),i=" j="len/2;">= 0 ( 1, 2, 4, 8, 16, .... ) without using C math library and arithmatic operators ( ie. *, /, +, - and math.h are not allowed)
#include void main(){ int i; for(i=0; i< na =" %d," b=" %d\n" t =" a;" a =" b;" b =" t;" a="10," b ="20;" e="10.0," f =" 20.0;" x = "string1" y = "string2" s1 =" {50," s2 =" {100," a =" (int" b =" (int" a =" 10;" b =" 20;" c =" (float" d =" (float" c =" 10.01;" d =" 20.02;">next == NULL) tail = head; if ((*head)->val == val) { *head = (*head)->next; } else head = &(*head)->next; } while((*tail)) { if ((*tail)->val == val) { *tail = (*tail)->prev; } else tail= &(*tail)->prev; }} /* Supporting (Verification) routine */ Link *DL_build();void DL_print(Link *); main(){ int val; Link *head; head = DL_build(); DL_print(head); printf("Enter the value to be deleted from the list : "); scanf("%d", &val); DL_delete(&head, val); DL_print(head);} Link *DL_build(){ int val; Link *head, *prev, *next; head = prev = next = NULL; while(1) { Link *new; printf("Enter the value for the list element (0 for end) : "); scanf("%d", &val); if (val == 0) break; new = (Link *) malloc(sizeof(Link)); new->val = val; new->prev = prev; new->next = next; if (prev) prev->next = new; else head = new; prev = new; } return (head);} void DL_print(Link *head){ Link *shead = head, *rhead; printf("\n****** Link List values ********\n\n"); while(head) { printf("%d\t", head->val); if (head->next == NULL) rhead = head; head = head->next; } printf("\n Reverse list \n"); while(rhead) { printf("%d\t", rhead->val); rhead = rhead->prev; } printf("\n\n");}

6 : What will be the output of this program ?
#include

main()
{
int *a, *savea, i;

savea = a = (int *) malloc(4 * sizeof(int));

for (i=0; i<4; i="0;"> savea = savea + sizeof(savea_type) * sizeof(int) ( by pointer arithmatic) => save = savea + sizeof(int) * sizeof(int) Note: You can verify the above by varing the type of 'savea' variable to char, double, struct, etc. Instead of statement 'savea += sizeof(int)' use savea++ thenthe values 0, 10, 20 and 30 will be printed. This behaviouris because of pointer arithmatic.
7 : Trace the program and print the output
#include

typedef int abc(int a, char *b);

int func2(int a, char *b)
{
a *= 2;
strcat(b, "func2 ");
return a;
}

int func1(int a, char *b)
{
abc *fn = func2;

a *= a;
strcat(b, "func1 ");
return (fn(a, b));
}

main()
{
abc *f1, *f2;
int res;
static char str[50] = "hello! ";

f1 = func1;
res = f1(10, str);
f1 = func2;
res = f1(res, str);

printf("res : %d str : %s\n", res, str);
}

Two function pointers f1 and f2 are declared of the type abc. whereas abc is a pointer to a function returns int.
func1() which is assigned to f1 is called first. It modifies the values of the parameter 'a' and 'b' to 100, "hello! func1 ". In func1(), func2() is called which further modifies the value of 'a' and 'b' to 200, "hello! func1 func2 " and returns the value of 'a' which is 200 to the main. Main calls f1() again after assigning func2() to f1. So, func2() is called and it returns the following value which will be the output of this program.

res : 400 str : hello! func1 func2 func2

The output string shows the trace of the functions called : func1() and func2() then again func2().

8 :
Write a program to reverse a Linked list within the same list

Solution:
#include typedef struct Link { int val; struct Link *next;} Link; /* Reverse List function */Link *SL_reverse(Link *head){ Link *revlist = (Link *)0; while(head) { Link *tmp; tmp = head; head = head->next; tmp->next = revlist; revlist = tmp; } return revlist;} /* Supporting (Verification) routines */ Link *SL_build(); main(){ Link *head; head = SL_build(); head = SL_reverse(head); printf("\nReversed List\n\n"); while(head) { printf("%d\t", head->val); head = head->next; }} Link *SL_build(){ Link *head, *prev; head = prev = (Link *)0; while(1) { Link *new; int val; printf("Enter List element [ 0 for end ] : "); scanf("%d", &val); if (val == 0) break; new = (Link *) malloc(sizeof(Link)); new->val = val; if (prev) prev->next = new; else head = new; prev = new; } prev->next = (Link *)0; return head;}

--------------------------------------------------------------------------------

9 : What will be the output of this program
#include

main()
{
int a=3, b = 5;

printf(&a["Ya!Hello! how is this? %s\n"], &b["junk/super"]);
printf(&a["WHAT%c%c%c %c%c %c !\n"], 1["this"],
2["beauty"],0["tool"],0["is"],3["sensitive"],4["CCCCCC"]);
}

Solution:In C we can index an array in two ways. For example look in to the following lines int a[3] = {10, 20, 30, 40}; In this example index=3 of array 'a' can be represented in 2 ways. 1) a[3] and 2) 3[a]i.e) a[3] = 3[a] = 40 Extend the same logic to this problem. You will get theoutput as follows Hello! how is this? super That is C

2006-05-01T22:47:00.000-07:00

C/C++ Questions:

1. What is encapsulation?
Containing and hiding information about an object, such as internal data structures and code. Encapsulation isolates the internal complexity of an object's operation from the rest
of the application. For example, a client component asking for net revenue from a business object need not know the data's origin.

2. What is inheritance?
Inheritance allows one class to reuse the state and behavior of another class. The derived class inherits the properties and method implementations of the base class and extends it by overriding methods and adding additional properties and methods.

3. What is Polymorphism??
Polymorphism allows a client to treat different objects in the same way even if they were created from different classes and exhibit different behaviors. You can use implementation inheritance to achieve polymorphism in languages such as C++ and Java. Base class object's pointer can invoke methods in derived class objects. You can also achieve polymorphism in C++ by function overloading and operator overloading.

4. What is constructor or ctor?
Constructor creates an object and initializes it. It also creates vtable for virtual functions. It is different from other methods in a class.

5. What is destructor?
Destructor usually deletes any extra resources allocated by the object.
What is default constructor?
Constructor with no arguments or all the arguments has default values.

6. What is copy constructor?
Constructor which initializes the it's object member variables ( by shallow copying) with another object of the same class. If you don't implement one in your class then compiler implements one for you.
for example:
Boo Obj1(10); // calling Boo constructor
Boo Obj2(Obj1); // calling boo copy constructor
Boo Obj2 = Obj1;// calling boo copy constructor

7. When are copy constructors called?
Copy constructors are called in following cases:
a) when a function returns an object of that class by value
b) when the object of that class is passed by value as an argument to a function
c) when you construct an object based on another object of the same class
d) When compiler generates a temporary object

8. What is assignment operator?
Default assignment operator handles assigning one object to another of the same class.
Member to member copy (shallow copy)

9. What are all the implicit member functions of the class? Or what are all the functions which compiler implements for us if we don't define one.?
default ctor copy ctor assignment operator default destructor address operator

10. What is conversion constructor?
constructor with a single argument makes that constructor as conversion ctor and it can be used for type conversion.
for example:
class Boo
{
public:
Boo( int i );
};
Boo BooObject = 10 ; // assigning int 10 Boo object

11. What is conversion operator??
class can have a public method for specific data type conversions.
for example:
class Boo
{
double value;
public:
Boo(int i )
operator double()
{
return value;
}
};
Boo BooObject;
double i = BooObject; // assigning object to variable i of type double. now conversion
operator gets called to assign the value.

12. What is diff between malloc()/free() and new/delete?
malloc allocates memory for object in heap but doesn't invoke object's constructor to
initiallize the object.
new allocates memory and also invokes constructor to initialize the object.
malloc() and free() do not support object semantics
Does not construct and destruct objects
string * ptr = (string *)(malloc (sizeof(string)))
Are not safe
Does not calculate the size of the objects that it construct
Returns a pointer to void
int *p = (int *) (malloc(sizeof(int)));
int *p = new int;
Are not extensible
new and delete can be overloaded in a class
"delete" first calls the object's termination routine (i.e. its destructor) and then
releases the space the object occupied on the heap memory. If an array of objects was
created using new, then delete must be told that it is dealing with an array by preceding
the name with an empty []:-
Int_t *my_ints = new Int_t[10];
...
delete []my_ints;

13. What is the diff between "new" and "operator new" ?
"operator new" works like malloc.
What is difference between template and macro??
There is no way for the compiler to verify that the macro parameters are of compatible types. The macro is expanded without any special type checking.
If macro parameter has a postincremented variable ( like c++ ), the increment is performed two times.
Because macros are expanded by the preprocessor, compiler error messages will refer to the expanded macro, rather than the macro definition itself. Also, the macro will show up in expanded form during debugging. for example:
Macro:
#define min(i, j) (i <>
T min (T i, T j)
{
return i < mystruct =" {" salaray =" 2000" b =" a;" temp =" x;" x =" y;" y =" x;" a="2," b="3;" num =" num" temp =" 2.0;" value =" cuberoot" temp =" 3L;" value =" cuberoot" parent_object_ptr =" new">show() // calls parent->show() i
now we goto virtual world...
class parent
{
virtual void Show()
{
cout << "i'm parent" << parent_object_ptr =" new">show() // calls child->show()

21. What is pure virtual function? or what is abstract class?
When you define only function prototype in a base class without and do the complete implementation in derived class. This base class is called abstract class and client won't able to instantiate an object using this base class.
You can make a pure virtual function or abstract class this way..

class Boo
{
void foo() = 0;
}
Boo MyBoo; // compilation error

22. What is Memory alignment??
The term alignment primarily means the tendency of an address pointer value to be a multiple of some power of two. So a pointer with two byte alignment has a zero in the least significant bit. And a pointer with four byte alignment has a zero in both the two least significant bits. And so on. More alignment means a longer sequence of zero bits in the lowest bits of a pointer.

23. What problem does the namespace feature solve?
Multiple providers of libraries might use common global identifiers causing a name collision when an application tries to link with two or more such libraries. The namespace feature surrounds a library's external declarations with a unique namespace that eliminates the potential for those collisions.
namespace [identifier] { namespace-body }
A namespace declaration identifies and assigns a name to a declarative region.
The identifier in a namespace declaration must be unique in the declarative region in which it is used. The identifier is the name of the namespace and is used to reference its
members.

24. What is the use of 'using' declaration?
A using declaration makes it possible to use a name from a namespace without the scope
operator.

25. What is an Iterator class?
A class that is used to traverse through the objects maintained by a container class. There
are five categories of iterators: input iterators, output iterators, forward iterators, bidirectional iterators, random access. An iterator is an entity that gives access to the contents of a container object without violating encapsulation constraints. Access to the contents is granted on a one-at-a-time basis in order. The order can be storage order (as in lists and queues) or some arbitrary order (as in array indices) or according to some ordering relation (as in an ordered binary tree). The iterator is a construct, which provides an interface that, when called, yields either the next element in the container, or some value denoting the fact that there are no more elements to examine. Iterators hide the details of access to and update of the elements of a container class. Something like a pointer.

26. What is a dangling pointer?
A dangling pointer arises when you use the address of an object after its lifetime is over.
This may occur in situations like returning addresses of the automatic variables from a function or using the address of the memory block after it is freed.

27. What do you mean by Stack unwinding?
It is a process during exception handling when the destructor is called for all local objects in the stack between the place where the exception was thrown and where it is
caught.

28. Name the operators that cannot be overloaded??
sizeof, ., .*, .->, ::, ?:

29. What is a container class? What are the types of container classes?
A container class is a class that is used to hold objects in memory or external storage. A container class acts as a generic holder. A container class has a predefined behavior and a well-known interface. A container class is a supporting class whose purpose is to hide the topology used for maintaining the list of objects in memory. When a container class contains a group of mixed objects, the container is called a heterogeneous container; when the container is holding a group of objects that are all the same, the container is called a homogeneous container.
30. What is inline function??
The __inline keyword tells the compiler to substitute the code within the function definition for every instance of a function call. However, substitution occurs only at the compiler's discretion. For example, the compiler does not inline a function if its address
is taken or if it is too large to inline.

31. What is overloading??
With the C++ language, you can overload functions and operators. Overloading is the practice of supplying more than one definition for a given function name in the same scope.
- Any two functions in a set of overloaded functions must have different argument lists.
- Overloading functions with argument lists of the same types, based on return type alone,
is an error.

32. What is Overriding?
To override a method, a subclass of the class that originally declared the method must declare a method with the same name, return type (or a subclass of that return type), and same parameter list.
The definition of the method overriding is:
• Must have same method name.
• Must have same data type.
• Must have same argument list.
Overriding a method means that replacing a method functionality in child class. To imply overriding functionality we need parent and child classes. In the child class you define the same method signature as one defined in the parent class.

33. What is "this" pointer?
The this pointer is a pointer accessible only within the member functions of a class,
struct, or union type. It points to the object for which the member function is called.
Static member functions do not have a this pointer.
When a nonstatic member function is called for an object, the address of the object is passed as a hidden argument to the function. For example, the following function call
myDate.setMonth( 3 ); can be interpreted this way:
setMonth( &myDate, 3 );
The object's address is available from within the member function as the this pointer. It is legal, though unnecessary, to use the this pointer when referring to members of the class.

34. What happens when you make call "delete this;"?
The code has two built-in pitfalls. First, if it executes in a member function for an extern, static, or automatic object, the program will probably crash as soon as the delete statement executes. There is no portable way for an object to tell that it was instantiated on the heap, so the class cannot assert that its object is properly instantiated. Second, when an object commits suicide this way, the using program might not know about its demise.
As far as the instantiating program is concerned, the object remains in scope and continues to exist even though the object did itself in. Subsequent dereferencing of the pointer can and usually does lead to disaster.
You should never do this. Since compiler does not know whether the object was allocated on the stack or on the heap, "delete this" could cause a disaster.

35. How virtual functions are implemented C++?
Virtual functions are implemented using a table of function pointers, called the vtable.
There is one entry in the table per virtual function in the class. This table is created by the constructor of the class. When a derived class is constructed, its base class is constructed first which creates the vtable. If the derived class overrides any of the base classes virtual functions, those entries in the vtable are overwritten by the derived class constructor. This is why you should never call virtual functions from a constructor: because the vtable entries for the object may not have been set up by the derived class constructor yet, so you might end up calling base class implementations of those virtual functions

36 What is name mangling in C++??
The process of encoding the parameter types with the function/method name into a unique name is called name mangling. The inverse process is called demangling.
For example Foo::bar(int, long) const is mangled as `bar__C3Fooil'.
For a constructor, the method name is left out. That is Foo::Foo(int, long) const is mangled as `__C3Fooil'.

37. What is the difference between a pointer and a reference?
A reference must always refer to some object and, therefore, must always be initialized; pointers do not have such restrictions. A pointer can be reassigned to point to different objects while a reference always refers to an object with which it was initialized.

38. How are prefix and postfix versions of operator++() differentiated?
The postfix version of operator++() has a dummy parameter of type int. The prefix version does not have dummy parameter.

39. What is the difference between const char *myPointer and char *const myPointer?
Const char *myPointer is a non constant pointer to constant data; while char *const
myPointer is a constant pointer to non constant data.

49. How can I handle a constructor that fails?
throw an exception. Constructors don't have a return type, so it's not possible to use
return codes. The best way to signal constructor failure is therefore to throw an exception.

50. How can I handle a destructor that fails?
Write a message to a log-file. But do not throw an exception.
The C++ rule is that you must never throw an exception from a destructor that is being called during the "stack unwinding" process of another exception. For example, if someone says throw Foo(), the stack will be unwound so all the stack frames between the throw Foo() and the } catch (Foo e) { will get popped. This is called stack unwinding.
During stack unwinding, all the local objects in all those stack frames are destructed. If one of those destructors throws an exception (say it throws a Bar object), the C++ runtime system is in a no-win situation: should it ignore the Bar and end up in the } catch (Foo e) { where it was originally headed? Should it ignore the Foo and look for a } catch (Bar e) {
handler? There is no good answer -- either choice loses information.
So the C++ language guarantees that it will call terminate() at this point, and terminate()
kills the process. Bang you're dead.

51. What is Virtual Destructor?
Using virtual destructors, you can destroy objects without knowing their type - the correct destructor for the object is invoked using the virtual function mechanism. Note that destructors can also be declared as pure virtual functions for abstract classes.
if someone will derive from your class, and if someone will say "new Derived", where
"Derived" is derived from your class, and if someone will say delete p, where the actual object's type is "Derived" but the pointer p's type is your class.
Can you think of a situation where your program would crash without reaching the breakpoint which you set at the beginning of main()?
C++ allows for dynamic initialization of global variables before main() is invoked. It is possible that initialization of global will invoke some function. If this function crashes the crash will occur before main() is entered.

52. Name two cases where you MUST use initialization list as opposed to assignment in constructors.
Both non-static const data members and reference data members cannot be assigned values; instead, you should use initialization list to initialize them.

53. Can you overload a function based only on whether a parameter is a value or a reference?
No. Passing by value and by reference looks identical to the caller.

54. What are the differences between a C++ struct and C++ class?
The default member and base class access specifiers are different.
The C++ struct has all the features of the class. The only differences are that a struct
defaults to public member access and public base class inheritance, and a class defaults to
the private access specifier and private base class inheritance.

55. What does extern "C" int func(int *, Foo) accomplish?
It will turn off "name mangling" for func so that one can link to code compiled by a C
compiler.

56. How do you access the static member of a class?
::

57. What is multiple inheritance (virtual inheritance)? What are its advantages and
disadvantages?
Multiple Inheritance is the process whereby a child can be derived from more than one parent class. The advantage of multiple inheritance is that it allows a class to inherit the functionality of more than one base class thus allowing for modeling of complex relationships. The disadvantage of multiple inheritance is that it can lead to a lot of confusion(ambiguity) when two base classes implement a method with the same name.

58. What are the access privileges in C++? What is the default access level?
The access privileges in C++ are private, public and protected. The default access level
assigned to members of a class is private. Private members of a class are accessible only
within the class and by friends of the class. Protected members are accessible by the class
itself and it's sub-classes. Public members of a class can be accessed by anyone.

60. What is a nested class? Why can it be useful?
A nested class is a class enclosed within the scope of another class. For example:
// Example 1: Nested class
//
class OuterClass
{
class NestedClass
{
// ...
};
// ...
};
Nested classes are useful for organizing code and controlling access and dependencies.
Nested classes obey access rules just like other parts of a class do; so, in Example 1, if
NestedClass is public then any code can name it as OuterClass::NestedClass. Often nested
classes contain private implementation details, and are therefore made private; in Example
1, if NestedClass is private, then only OuterClass's members and friends can use
NestedClass.
When you instantiate as outer class, it won't instantiate inside class.

61. What is a local class? Why can it be useful?
local class is a class defined within the scope of a function -- any function, whether a
member function or a free function. For example:
// Example 2: Local class
//
int f()
{
class LocalClass
{
// ...
};
// ...
};
Like nested classes, local classes can be a useful tool for managing code dependencies.

62. Can a copy constructor accept an object of the same class as parameter, instead of reference of the object?
No. It is specified in the definition of the copy constructor itself. It should generate an error if a programmer specifies a copy constructor with a first argument that is an object and not a reference.

63. (From Microsoft) Assume I have a linked list contains all of the alphabets from ‘A’ to ‘Z’.
I want to find the letter ‘Q’ in the list, how does you perform the search to find the ‘Q’?
How do you write a function that can reverse a linked-list? (Cisco System)
void reverselist(void)
{
if(head==0)
return;
if(head->next==0)
return;
if(head->next==tail)
{
head->next = 0;
tail->next = head;
}
else
{
node* pre = head;
node* cur = head->next;
node* curnext = cur->next;
head->next = 0;
cur->next = head;
for(; curnext!=0; )
{
cur->next = pre;
pre = cur;
cur = curnext;
curnext = curnext->next;
}
curnext->next = cur;
}
}
64. How do you find out if a linked-list has an end? (i.e. the list is not a cycle)
You can find out by using 2 pointers. One of them goes 2 nodes each time. The second one
goes at 1 nodes each time. If there is a cycle, the one that goes 2 nodes each time will
eventually meet the one that goes slower. If that is the case, then you will know the
linked-list is a cycle.

65. How can you tell what shell you are running on UNIX system?
You can do the Echo $RANDOM. It will return a undefined variable if you are from the
C-Shell, just a return prompt if you are from the Bourne shell, and a 5 digit random numbers
if you are from the Korn shell. You could also do a ps -l and look for the shell with the
highest PID.

66. What is Boyce Codd Normal form?
A relation schema R is in BCNF with respect to a set F of functional dependencies if for all
functional dependencies in F+ of the form a->b, where a and b is a subset of R, at least one
of the following holds:
• a->b is a trivial functional dependency (b is a subset of a)
• a is a superkey for schema R
Could you tell something about the Unix System Kernel?
The kernel is the heart of the UNIX openrating system, it’s reponsible for controlling the computer’s resouces and scheduling user jobs so that each one gets its fair share of resources.

67. What is a Make file?
Make file is a utility in Unix to help compile large programs. It helps by only compiling
the portion of the program that has been changed

68. How do you link a C++ program to C functions?
By using the extern "C" linkage specification around the C function declarations.

Explain the scope resolution operator.
Design and implement a String class that satisfies the following:
Supports embedded nulls
Provide the following methods (at least)
Constructor
Destructor
Copy constructor
Assignment operator
Addition operator (concatenation)
Return character at location
Return substring at location
Find substring
Provide versions of methods for String and for char* arguments
Suppose that data is an array of 1000 integers. Write a single function call that will sort
the 100 elements data [222] through data [321].
Answer: quicksort ((data + 222), 100);
What is a modifier?
What is an accessor?

Differentiate between a template class and class template.

When does a name clash occur?

Define namespace.

What is the use of ‘using’ declaration.

What is an Iterator class?

List out some of the OODBMS available.

List out some of the object-oriented methodologies.

What is an incomplete type?

What is a dangling pointer?

Differentiate between the message and method.

What is an adaptor class or Wrapper class?

What is a Null object?

What is class invariant?
What do you mean by Stack unwinding?
Define precondition and post-condition to a member function.

What are the conditions that have to be met for a condition to be an invariant of the class?

What are proxy objects?

Name some pure object oriented languages.

Name the operators that cannot be overloaded.

What is a node class?

What is an orthogonal base class?

What is a container class? What are the types of container classes?

What is a protocol class?

What is a mixin class?

What is a concrete class?

What is the handle class?

What is an action class?

When can you tell that a memory leak will occur?
What is a parameterized type?
Differentiate between a deep copy and a shallow copy?
What is an opaque pointer?
What is a smart pointer?
What is reflexive association?
What is slicing?
What is name mangling?
What are proxy objects?
What is cloning?
Describe the main characteristics of static functions.
Will the inline function be compiled as the inline function always? Justify.
Define a way other than using the keyword inline to make a function inline.
How can a '::' operator be used as unary operator?
What is placement new?
What do you mean by analysis and design?
What are the steps involved in designing?

What are the main underlying concepts of object orientation?

What do u meant by "SBI" of an object?

Differentiate persistent & non-persistent objects?

What do you meant by active and passive objects?

What is meant by software development method?

What do you meant by static and dynamic modeling?

How to represent the interaction between the modeling elements?

Why generalization is very strong?

Differentiate Aggregation and containment?
Can link and Association applied interchangeably?

What is meant by "method-wars"?

Whether unified method and unified modeling language are same or different?

Who were the three famous amigos and what was their contribution to the object community?

Differentiate the class representation of Booch, Rumbaugh and UML?

What is an USECASE? Why it is needed?

Who is an Actor?

What is guard condition?

Differentiate the following notations?

USECASE is an implementation independent notation. How will the designer give the
implementation details of a particular USECASE to the programmer?

Suppose a class acts an Actor in the problem domain, how to represent it in the static
model?

Why does the function arguments are called as "signatures"?

What is the difference between C and C++? Would you prefer to use one over the other?
C is based on structured programming whereas C++ supports the object-oriented programming paradigm. Due to the advantages inherent in object-oriented programs such as modularity and reuse, C++ is preferred. However almost anything that can be built using C++ can also be built using C.
Explain operator precendence.
Operator precedence is the order in which operators are evaluated in a compound expression. For example, what is the result of the following expression?
6 + 3 * 4 / 2 + 2 Here is a compound expression with an insidious error.
while ( ch = nextChar() != '\0' ) The programmer's intention is to assign ch to the next character then test that character to see whether it is null. Since the inequality operator has higher precendence than the assignment operator, the real result is that the next character is compared to null and ch is assigned the boolean result of the test (i.e. 0 or 1).
What are the access privileges in C++? What is the default access level?
The access privileges in C++ are private, public and protected. The default access level assigned to members of a class is private. Private members of a class are accessible only within the class and by friends of the class. Protected members are accessible by the class itself and it's sub-classes. Public members of a class can be accessed by anyone.
What is data encapsulation?
Data Encapsulation is also known as data hiding. The most important advantage of encapsulation is that it lets the programmer create an object and then provide an interface to the object that other objects can use to call the methods provided by the object. The programmer can change the internal workings of an object but this transparent to other interfacing programs as long as the interface remains unchanged.
What is inheritance?
Inheritance is a mechanism through which a subclass inherits the properties and behavior of its superclass; the subclass has a ISA relationship with the superclass. For example Vehicle can be a superclass and Car can be a subclass derived from Vehicle. In this case a Car ISA Vehicle. The superclass 'is not a' subclass as the subclass is more specialized and may contain additional members as compared to the superclass. The greatest advantage of inheritance is that it promotes generic design and code reuse.
What is multiple inheritance? What are its advantages and disadvantages?
Multiple Inheritance is the process whereby a sub-class can be derived from more than one super class. The advantage of multiple inheritance is that it allows a class to inherit the functionality of more than one base class thus allowing for modeling of complex relationships. The disadvantage of multiple inheritance is that it can lead to a lot of confusion when two base classes implement a method with the same name.
What is polymorphism?
Polymorphism refers to the ability to have more than one method with the same signature in an inheritance hierarchy. The correct method is invoked at run-time based on the context (object) on which the method is invoked. Polymorphism allows for a generic use of method names while providing specialized implementations for them.
What do the keyword static and const signify?
When a class member is declared to be of a static type, it means that the member is not an instance variable but a class variable. Such a member is accessed using Classname.Membername (as opposed to Object.Membername). Const is a keyword used in C++ to specify that an object's value cannot be changed.
What is a static member of a class?
Static data members exist once for the entire class, as opposed to non-static data members, which exist individually in each instance of a class.
How do you access the static member of a class?<ClassName>::.
What feature of C++ would you use if you wanted to design a member function that guarantees to leave this object unchanged?
It is const as in: int MyFunc? (int test) const;
What is the difference between const char *myPointer; and char *const myPointer;?
const char *myPointer; is a non-constant pointer to constant data; while char *const myPointer; is a constant pointer to non-constant data.
How is memory allocated/deallocated in C? How about C++?
Memory is allocated in C using malloc() and freed using free(). In C++ the new() operator is used to allocate memory to an object and the delete() operator is used to free the memory taken up by an object.
What is the difference between public, protected, and private members of a class?
Private members are accessible only by members and friends of the class. Protected members are accessible by members and friends of the class and by members and friends of derived classes. Public members are accessible by everyone.
How do you link a C++ program to C functions?
By using the extern "C" linkage specification around the C function declarations.
The candidate should know about mangled function names and type-safe linkages. They should explain how the extern "C" linkage specification statement turns that feature off during compilation so that the linker properly links function calls to C functions.
What does extern "C" int func(int *, Foo) accomplish?
It will turn off "name mangling" for func so that one can link to code compiled by a C compiler.
Why do C++ compilers need name mangling?
Name mangling is the rule according to which C++ changes function names into function signatures before invoking the linker. Mangled names are used by the linker to differentiate between different functions with the same name.
What is function's signature?
function's signature is its name plus the number and types of the parameters it accepts.
What are the differences between a C++ struct and C++ class?
The default member and base class access specifiers are different.
The C++ struct has all the features of the class. The only differences are that a struct defaults to public member access and public base class inheritance, and a class defaults to the private access specifier and private base class inheritance.
What is the difference between function overloading and function overriding?
Overloading is a method that allows defining multiple member functions with the same name but different signatures. The compiler will pick the correct function based on the signature. Overriding is a method that allows the derived class to redefine the behavior of member functions which the derived class inherits from a base class. The signatures of both base class member function and derived class member function are the same; however, the implementation and, therefore, the behavior will differ.
Can you overload a function based only on whether a parameter is a value or a reference?
No. Passing by value and by reference looks identical to the caller.
Can derived class override some but not all of a set of overloaded virtual member functions inherited from the base class?
Compiler will allow this, but it is a bad practice since overridden member functions will hide all of the inherited overloads from the base class. You should really override all of them.
What is the difference between assignment and initialization in C++?
Assignment changes the value of the object that has already been constructed. Initialization constructs a new object and gives it a value at the same time.
Name two cases where you MUST use initialization list as opposed to assignment in constructors.
Both non-static const data members and reference data members cannot be assigned values; instead, you should use initialization list to initialize them.
When are copy constructors called?
Copy constructors are called in three cases: when a function returns an object of that class by value, when the object of that class is passed by value as an argument to a function, and, finally, when you construct an object based on another object of the same class (Circle c1=c2;).

Medior Questions
What is the difference between delete and delete[]?delete deletes one object; delete[] deletes an array of objects.
What is the difference between non-virtual and virtual functions?
The behavior of a non-virtual function is known at compile time while the behavior of a virtual function is not known until the run time.
What is a pure virtual function?
A pure virtual function is a function declared in a base class that has no definition relative to the base.
How do you know that your class needs a virtual destructor?
If your class has at least one virtual function, you should make a destructor for this class virtual. This will allow you to delete a dynamic object through a pointer to a base class object. If the destructor is non-virtual, then the wrong destructor will be invoked during deletion of the dynamic object.
What is an abstract base class?
A class that has one or more pure virtual functions.
What is your reaction to this line of code?
delete this;
It's not a good practice.
A good programmer will insist that the statement is never to be used if the class is to be used by other programmers and instantiated as static, extern, or automatic objects. That much should be obvious.
The code has two built-in pitfalls. First, if it executes in a member function for an extern, static, or automatic object, the program will probably crash as soon as the delete statement executes. Second, when an object commits suicide this way, the using program might not know about its demise. As far as the instantiating program is concerned, the object remains in scope and continues to exist even though the object did itself in.
What is a default constructor?
A constructor that has no arguments or one where all the arguments have default argument values.
The candicate should know that if you don't code a default constructor, the compiler provides one if there are no other constructors. If you are going to instantiate an array of objects of the class, the class must have a default constructor.
Why do you have to provide your own copy constructor and assignment operator for classes with dynamically allocated memory?
If you don't, the compiler will supply and execute the default constructor and the assignment operator, but they will not do the job correctly. The default assignment operator does memberwise assignment and the default copy constructor does memberwise copy. In both cases you will only assign and manipulate pointers to dynamic memory, which will lead to memory leaks and other abnormalities. You should write your own assignment operator and copy constructor, which would copy the pointer to memory so that each object has its own copy.
Explain the ISA and HASA class relationships. How would you implement each in a class design?
A specialized class "is a" specialization of another class and, therefore, has the ISA relationship with the other class. An Employee ISA Person. This relationship is best implemented with inheritance. Employee is derived from Person. A class may have an instance of another class. For example, an Employee "has a" Salary, therefore the Employee class has the HASA relationship with the Salary class. This relationship is best implemented by embedding an object of the Salary class in the Employee class.
What is the difference between a shallow copy and a deep copy?
A shallow copy simply creates a new object and inserts in it references to the members of the original object. A deep copy constructs a new object and then creates in it copies of each of the members of the original object.
What is the difference between MyClass p; and MyClass p();?
MyClass p; creates an instance of class MyClass by calling a constructor for MyClass. MyClass p(); declares function p which takes no parameters and returns an object of class MyClass by value.
What issue do auto_ptr objects address?
If you use auto_ptr objects you would not have to be concerned with heap objects not being deleted even if the exception is thrown.
What functions does C++ silently write and call?
Constructors, destructors, copy constructors, assignment operators, and address-of operators.
Does the compiler guarantee that initializers will be executed in the same order as they appear on the initialization list?
No. C++ guarantees that base class subobjects and member objects will be destroyed in the opposite order from which they were constructed. This means that initializers are executed in the order, which supports the above-mentioned guarantee.

Senior Questions
Who is Brad Cox?He authored Object-oriented Programming, An Evolutionary Approach, a book that is generally credited with launching today's industry-wide enthusiasm for object technology.
Who is Grady Booch?Grady Booch has been an object- based/oriented advocate for some time. His latest notations are often referred to as simply the "Booch" method or notation.
How are prefix and postfix versions of operator++() differentiated?
The postfix version of operator++() has a dummy parameter of type int. The prefix version does not have dummy parameter.
Can you think of a situation where your program would crash without reaching the breakpoint which you set at the beginning of main()?
C++ allows for dynamic initialization of global variables before main() is invoked. It is possible that initialization of global will invoke some function. If this function crashes the crash will occur before main() is entered.
Is there any problem with the following:
char *a = NULL;char& p = *a;?
The result is undefined. You should never do this. A reference must always refer to some object.

Advanced Questions
What is a mutable member?
One that can be modified by the class even when the object of the class, or the member function doing the modification, is const.
Why were the templates introduced?
Many data structures and algorithms can be defined independently of the type of data they work with. You can increase the amount of shared code by separating data-dependent portions from data-independent portions, and templates were introduced to help you do that.
What is the difference between static_cast(*this) += 5; and static_cast(*this) += 5;?
If you cast *this to be an RWTime object, the copy constructor for RWTime will be called and the new object will be the target of the assignment, *this will remain unchanged. Hardly what you want. The second instance actually increments this by 5.

Traverse the tree:

Preorder traversal
Visit the root
Traverse the left subtree
Traverse the right subtree

Inorder traversal
Traverse the left subtree
Visit the root
Traverse the right subtree

Postorder traversal
Traverse the left subtree
Traverse the right subtree
Visit the root

What's the difference between "const Fred* p", "Fred* const p" and "const Fred* const p"?

You have to read pointer declarations right-to-left.
- const Fred* p means "p points to a Fred that is const" — that is, the Fred object can't be changed via p.
- Fred* const p means "p is a const pointer to a Fred" — that is, you can change the Fred object via p, but you can't change the pointer p itself.
- const Fred* const p means "p is a const pointer to a const Fred" — that is, you can't change the pointer p itself, nor can you change the Fred object via p.