20 brush-up java questions and answers before interview

1. What is immutable object? Can you write immutable object??

2. What is the difference between creating String as new() and literal?

3. What is constructor chaining and how is it achieved in Java ?

4. what is synchronization in respect to multi-threading in java?

5. when InvalidMonitorStateException is thrown? why?

6. What happens when i make a static method as synchronized?

7. What are Marker Interfaces in Java? and why?

8. Why multiple inheritance is not supported in java?

9. What is difference between StringBuffer and StringBuilder in Java ?

10. What is Difference between Hashtable and HashMap in Java?

11. What is difference between Vector and ArrayList in Java?

12. Why character array is better than String for storing password in java.

13. Why main method is public static in java.

14. Can we override main method in java?

15. Can we overload the main method in java?

16. Why can't static methods be overridden?

17. Difference b/w Transient and Volatile Modifiers.

18. Sort the ArrayList using Comparator and Comparable.

19. What are the new features in jdk 1.5.

20. Write one java program having all OOPs features.

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