A job interview can be scary at the best of times. In the current economy, the process is even more intimidating. What sort of questions would you expect? What level of discussion are you likely to enter into in a Java interview? You ­ the readers ­ responded with a wonderful array of questions.

Warm Up Questions
How many interfaces can an interface extend?
Hugh McBride

Is Java fully object-oriented? If yes, why?
Yogaraj Jayaprakasam

Explain garbage collection in Java and the impact upon memory usage and performance in two of the common algorithms for determining when the space allocated to objects can be returned to free storage.
Harry Kaplan

What is the difference between wait and sleep and why is it important?
Martin Smith

Can you store null in a Hashtable?
Fatih Karakurt

How do you allocate memory in Java?
Ratan

What are the four modes of access protection in Java, and how do they behave? What's special about "protected" access?
Bruce Wilson

Java as a Language
Given the opportunity to dictate changes for the next Java release, what would you fix?
Brian Gentry

How do you deprecate a method?
John Davies

What is the difference between overloading a method and overriding a method?
Vikrant

What is reflection? When would you use it?
Jill Qian

How do inner classes impact OO design? Do they help create better OO designs?
Mohan Radhakrishnan

Design-Type Issues
Assuming you know the philosophy of the Java object model, the syntax of the Java language, how to use the Java platform, and the semantics of the specific APIs that are pertinent to the job you are seeking ­ how do you decide what to do when confronted with a need for new functionality?
Lee Hall

An interface doesn't contain any implementation. Why would you want to use it?
Dushyanth Inguva

What's an immutable object? What are some examples? Why is immutability important in Java? How would you create an immutable class?
Bruce Wilson

If you needed to hold a collection of objects within a class, how would you do it?
David Kavanagh

How can you leverage the salient features of Java to create an extensible and pluggable component framework?
David Forden

Political Questions
Where do you see Java in relation to other languages and development environments? What are its strengths?
Scott Frazor

What three things would you most like to change about the Java language? Not API stuff like "make AWT/Swing faster," but rather language-level specifics such as the assertions that were recently added or the semantics of public/private/package visibility.
Eric Rizzo

Assuming you'll only deploy on Windows platforms, give three reasons why you would choose Java instead of C#.
Jim Long

Summary
These questions covered all facets of Java, and we presented a few here so you would know what to expect. If you recently had an interview, we'd love to know the sort of questions you were asked.