• When would U use thread pooling ?
• How would U implement a thread pool ?
• What are worker queues and worker threads ?
• Have U explored the java.util.concurrent package in Java 5.0 ?
• What is a deadlock and a race condition ?

What's the advantage of adding a "serialVersionUID" to a Java source file?

EJB Questions:
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Give some examples of services offered by a EJB container?. What's the advantage of component model of software design?

How does the EJB container manage to intercept calls to a remote object and apply transactions, security?

Can an Entity EJB be dedicated to a single client?

What protocol is used when a EJB client communicates with a EJB server?

What's the difference btw EJB and CORBA models?

What's the difference between JSP include directive and include element?

Struts Questions

-- Explain the Struts architecture.
-- What are form-beans. Why are they required. Heard of DynaActionForm? Are form-beans required in Struts2?
-- How is form validation done in Struts?
-- Is validation done on server side of client side or both? Javascript vs Java?
-- Can there be more than one struts-config file?.
-- Can I change the name of the struts config file?
-- Can I use Tiles, Velocity template engine with struts?

-- What is the use of custom tags in JSP?
-- Would U use JSTL or Struts custom tags in Ur JSP pages?
-- What does the TLD file contain?
-- Difference between Struts 1.x and Struts 2.x?
-- How to use the MDC/NDC in Log4J with Struts? Where to put in the code? Which common place?
-- Can Struts2 be used with JSF?
-- How is AJAX handled in Struts 2?
-- Can we use JQuery instead of DWR?
-- Tiles vs IFrame? Pros and cons..
-- Can a single webapplication have some resources to be accessed thru HTTP and some by HTTPS?

If I declare a class as 'protected', can other classes in the same package access the class?

What is "inversion of control" design pattern? What is "dependency injection" ?

Suppose U have a data collection (say a "arraylist"). U want to make sure that no one else can modify it. i.e. U want to make it immutable. How will U do it?

What would U do if U need a "Multi-Map" collection? i.e. U have a collection where one key may map to many values.

Can a Java class be private or protected?

What is the advantage of Inner classes over encapsulation?
I can make a class as "package" access. Will this not suffice ? Why do I need Inner classes?

How will U debug a Java program that has several threads running?
If U place a break-point somewhere, will all threads be suspended or only a single thread?

What's the difference between the 'java.exe' and 'javaw.exe' processes?
When to use what?

A circular project dependency occurs when two or more projects depend on each other. For example: FileOne in ProjectA depends on FileTwo in ProjectB, and FileThree in ProjectB depends on FileFour back in ProjectA.

How will U solve such dependencies in Java ?

Suppose U have a file that needs to be shared between a Java application and a non-Java application for writing/reading. How will U do it ?

Why does the Java language make it mandatory to have wait() and notify() inside a synchronized block?

What's the difference btw the notify() and notifyAll() method?
When should U use what?
Why should wait() and notify() methods be placed inside a synchronized block?

What is a race condition? How is it different from a dead-lock?

What's the difference between a CORBA object and a servant?

• What are boot-strap classes in Java?
• What is a Class Loader? Can we write our own Class Loader?
• What is class Class?

What is obfuscation and how does it work?
How to Decompilers work ?

U develop an application that supports various languages using globalization. How will U compare or sort strings?. Will the == or equals() method suffice?

What is the double-buffering technique used in almost all GUIs? Do Java Swing components use double-buffering?

• Can the return type of a overloaded method be different?
• Can I override a private method of a class? (Remember that private methods are not accessible to subclasses)

• How is synchronization done between threads?
• What is a object lock or mutex?
• What is a class lock? How can we obtain a class lock.
• Can I use any arbitary object as a lock? (For e.g. Object myLock = new Object() )

• What's the difference between an ArrayList and a Vector?
• Can I make a ArrayList shynchronized?
• What's the difference between a List and a Set?
• What data-structures have U used in Ur project and what were Ur deciding factors on the choice of collection object?
• Ever heard of a "Muti-Map" collection object?
• Which collection object in Java is best if U want fast searching?
• How will U do a binary search on a ArrayList?

What's the difference between AWT and SWING? Ever heard of SWT?

• How does GC occur in Java?
• Ever heard of soft references, weak references, phantom references? What is their use?
• When do U get a "OutOfMemory" error?
• What are root nodes?