1. What is difference between String & StringBuffer?
  2. What is difference between StringBuffer & StringBuilder?
  3. What is overloading?
  4. Explain about “automatic promotion” in overloading?
  5. What is overriding?
  6. Explain about method hiding?
  7. What is difference between super and this keyword?
  8. Explain about IS-A Relationship?
  9. Explain about HAS-A Relationship?
  10. What is method signature?
  11. Can we override variables?
  12. What is Data hiding,abstraction and encapsulation?
  13. What is Abstract class?
  14. What is Abstract method?
  15. What is an interface?
  16. How to implement multiple inheritanc using interfaces with example?
  17. Can we instanciate Abstract class and interface?
  18. What is interface ambiguity?
  19. Can we declare instance variables in abstract class?
  20. Which class is the super class for entire exception handling?
  21. What is checked and unchecked exceptions?
  22. Can we write try with mupiple catch blocks?if yes,what should be the order of catch blocks?
  23. What is the use of finally block?
  24. Is there any case where finally block will not be execute?
  25. What is the difference between exception and error?
  26. When “StackOverFlow error” will occur?
  27. What is the difference between thow and throws keyword?
  28. Explain about customized exceptions?
  29. What is the diffrence between array and collections?
  30. What is the difference between List and Set?
  31. Explian the difference between ArrayList and Vector?
  32. What is the difference between ArrayList and LinkedList?
  33. How to make ArrayList as synchronized version?
  34. Can we insert duplicate objects in set, if insert duplicate objects will we get any error?
  35. What is the difference between HashSet and LinkedHashSet?
  36. Explain about TreeSet?
  37. What is the difference between Comparable and Comparator?
  38. What is the difference between HashMap and Hashtable?
  39. What is the difference between HashMap and LinkedHashMap?
  40. What is the difference between Enumeration,Iterator and ListIterator?
  41. Explain about Collections and Arrays Utility classes?
  42. How can we convert Array to List and List to array?