33 Java Interview Questions

1. What are the thread states in java ?
2. List all the types of nested class ?
3. How to increase the heap memory of the JVM ?
4. Name three JVMs ?
5. What is the quickest type of Map ?
6. How do you redirect the System.out ( "standard" output stream ) to a file ?
7. A class that supports serializarion must implement serializable, if its base class is not serizable then what must it have. ?
8. Which method should you override when writing a Customer Class Loader ?
9. Name the standard class loaders ?
10. What is the signature of readResolve() and what is it used for ?
11. Other than using externizable, how can you handle custom serilization ?
12. In java 6, how can you see the assembly code that the JIT is creating ?
13. Name 10 Ways to Reduce Lock Contention in Threaded Programs ?
14. List 4 Collection Classes and 4 Collection Interfaces ?
15. How do you create an array using reflection
16. Describethe following exceptions : CloneNotSupportedException, ClassNotFoundException, ArrayStoreException, ClassCastException, ConcurrentModificationException, IllegalMonitorStateException, UnsupportedOperationException.
17 With java collections, whats the difference between Offer(E e) and Add(E e).
18 Can a top level class be have a protected class modifier
19 Does this produce a runtime error
public class Test {
public static void main(String... args) {
Object o = new Object() {
public boolean equals(Object t) {
return t.equals("hi");
}
};
System.out.println(o.equals("hi"));
}
}
20 What is the difference between weak and soft references
21 What is the difference between NoClassDefFoundError and a ClassNotFoundException
22 When should you use Serializable and when should you use Externalizable
23 How do you create a singleton
24 What is the difference between parameters and arguments
25 what is escape analysis
26 what are memory barriers
27 how/when does instruction reodering occur in java
28 what is object orientation
29 explain double checked locking
30 is there ever a case when a singleton may return a differnt instance
30 what is instruction reordering and when / where is it used
31 If the compareTo method of a comparable object returns zero are they equal
32 what are synthetic bridge methods
33 write a class that implements the following :
- if the object has been seen before, returns the same integer
- if the object has not been seen before returns a different integer.
page revision: 61, last edited: 04 Apr 2013 10:45