Interview Questions on Core Java

I am consolidating the questions asked during the any technical interview in different top MNCs:

  1. What is the difference between and Interface and Abstract Class?
  2. Can we create an Abstract Class without any abstract Method into it?
  3. How to make a lock at class level?
  4. What are different states in Threading?
  5. Do we have alternative to Inheritance, How this alternative is useful over inheritance?
  6. What does a method or field is “static” means?
  7. What is the difference between JVM/JRE/JDK?
  8. What is Synchronization and how it works?
  9. What is the difference between ArrayList and Vector?
  10. What is the default size of ArrayList?
  11. How to synchronized Arraylist?
  12. What is the difference between Collection and Collections?
  13. What is the difference between HashTable and HashMap?
  14. How to get intersection for to List having common elements into it?
  15. What is difference between List and a Set?
  16. When to use ArrayList and LinkedList?
  17. How to iterate HashMap without Key for Value?
  18. Which Design Pattern an Iterator follow?
  19. What is cursor in java collections framework?