Core Java Q

1. What is JVM (Java Virtual Machine)?
2. What is JIT (Just-in-Time) Compilation?
3. What is Object Oriented Programming?
4. What’s a Class?
5. What’s an Object?
6. What’s the relation between Classes and Objects?
7. What are different properties provided by Object-oriented systems?
8. How do you implement inheritance in Java?
9. How can we implement polymorphism in Java?
10.What’s an interface and how will you go about implementing an interface?
11. What is an Abstract class?
12. What are Abstract methods?
13. What’s the difference between “Abstract” classes and “Interfaces”?
14. What’s difference between Static and Non-Static fields of a class?
15. What are inner classes and what’s the practical implementation of inner classes?
16. What are packages?
17. What is a constructor in class?
18. Can constructors be parameterized?
19. Can you explain transient and volatile modifiers?
20. What is the use if “instanceof ” keyword?
21. What are Native methods in Java?
22. Explain in depth Garbage collector?
23. How does the garbage collector determine that the object has to be marked for deletion?
24. Can you explain “finalize()” method?
25. How can we force the garbage collector to run?
26. What’s the main difference between “Switch” and “If ” comparison?
27. What’s the use of JAVAP tool?
28. What are applets?
29. In which package is the applet class located?
30. What are native interfaces in Java?
31. what are Class loader’s?
32. what is Bootstrap, Extension and System Class loader?
33. Can you explain the flow between bootstrap, extension and system class loader?
34. Can you explain how can you practically do dynamic loading?
35. How can you copy one array in to a different array?
36. Can you explain the core collection interfaces?
37. Can you explain in brief the collection classes which implement the collection interfaces?
38. What’s the difference between standard JAVA array and ArrayList class?
39. What’s the use of “ensureCapacity” in ArrayList class?
40. How can we obtain an array from an ArrayList class?
41. What is “LinkedList” class for?
42. Can you explain HashSet class in collections?
43. what is LinkedHashSet class?
44. what is a TreeSet class?
45. what’s the use of Comparator Interface?
46. How can we access elements of a collection?
47. What is Map and SortedMap Interface?
48. Have you used any collection algorithm?
49. Can we create our own exception class?
50. What are chained exceptions?
51. What is serialization?
52. How do we implement serialization actually?
53. What’s the use of Externalizable Interface?