Test your core java basics by answering these question before you head for java interview .

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Test your core java basics by answering these question before you head for java interview .


  1. What is the difference between final, finally, and finalize()?
  2. What is the difference between a HashMap and a Hashtable?
  3. What is Hash Collision? How is it being resolved internally?
  4. What is the difference between checked and unchecked (e.g: RuntimeException/Error) Exceptions? Give some examples.
  5. Names some of the primary structures in the Collections API and what are their semantics, i.e. when do you use one vs. another?
  6. Between an ArrayList and a LinkedList, when do you use one over another?
  7. What is innerClass and anonymous class in java? What is the purpose of anonymous class?
  8. · Difference between runnable and callable?
  9. · What is intrinsic and re-entrant lock? When it''s useful?
  10. What is piped stream and concept of NIO - which API did you use? Why NIO is better compare to IO?
  11. What is Future class?
  12. · How do you write a daemon thread in Java?
  13. Difficult
  14. Explain Java class loaders. Explain dynamic class loading.
  15. How does Java allocate stack and heap memory?
  16. What do you know about the Java garbage collector?
  17. What does old generation vs. new generation mean and why is it useful?
  18. What is AtomicInteger? How is it implemented?
  19. ConsurrentHAshMap - why it gives better performance in multi threaded apps?
  20. · What is consistent hashing?