It was a phone interview, 2 people were on the call, they asked me to tell in 5 - 10 sentences some points which I want to highlight from resume / not mentioned on the resume. Later they asked me to explain my latest project which I am working on, and later asked me around 20 core Java questions.

1. what is java polymorphism - how java implements polymorphism?
2. purpose of volatile keyword
3. can top level class be declared static?
4. when is object.finalise method, when is it called?
5. Can we syncronise the static method
6. Can we invoke non static method from static method on same class
7. Producer and consumer pattern explain??
8. Which design pattern u used in ur projects?
9. Describe heirarchy of exception class
10. Java collection api - describe a few?
11. Describe transient variable
12. Describe final keyword
13. Multithreading - how to create multiple thread, describe how to start new thread
14. Difference between runnable and callable
15. Difference between treemap and hashmap?
16. String, string builder and string buffer differences
17. Java io apis which u used -?
18. Singleton pattern - explain
19. How do you make class singleton.