Common Java interview questions

Here is a list of common Java interview questions that you may encounter during a job interview:

1. What is Java, and what are its key features?
2. Can you explain the difference between a JDK, JRE, and JVM?
3. What is the significance of the main method in Java?
4. Can you explain the difference between primitive and reference data types in Java?
5. Can you explain inheritance and polymorphism in Java?
6. What is an exception in Java, and how do you handle exceptions in your code?
7. Can you explain the difference between checked and unchecked exceptions in Java?
8. What is the difference between a class and an object in Java?
9. Can you explain the concept of encapsulation in Java?
10. What is the difference between a static and non-static method in Java?
11. Can you explain the difference between a HashMap and a TreeMap in Java?
12. Can you explain the difference between an ArrayList and a LinkedList in Java?
13. What is a Collection framework in Java, and can you give an example of a Collection type?
14. Can you explain the difference between a String and a StringBuilder in Java?
15. What is a Thread in Java, and how do you create and run a Thread?
16. Can you explain the difference between a runnable and a callable interface in Java?
17. Can you explain the concept of multithreading and concurrency in Java?
18. What is the difference between a synchronized and an unsynchronized block in Java?
19. Can you explain the difference between a serialization and a deserialization in Java?
20. Can you explain the difference between a final, finally, and finalize in Java?
21. What is the difference between an abstract class and an interface in Java?
22. Can you explain the concept of an interface in Java, and how it can be used?
23. Can you explain the difference between a constructor and a method in Java?
24. Can you explain the difference between a static and non-static inner class in Java?
25. What is the difference between a static and non-static block in Java?
26. Can you explain the difference between a break and a continue statement in Java?
27. What is an enum in Java, and how can it be used?
28. Can you explain the difference between the instance-of and typeof operator in Java?
29. What is a package in Java, and how can it be used?
30. Can you explain the difference between a private and protected method in Java?
31. Can you explain the difference between the == operator and the .equals() method in Java?
32. What is an anonymous inner class in Java, and how can it be used?
33. Can you explain the difference between a transient and a volatile keyword in Java?
34. What is a class loader in Java, and how does it work?
35. Can you explain the difference between a compile-time and a run-time error in Java?
36. What is the difference between a static and dynamic binding in Java?
37. Can you explain the difference between a deep and a shallow copy in Java?
38. Can you explain the difference between a deadlock and a livelock in Java?
39. What is the difference between a stack and a queue in Java?
40. Can you explain the difference between a Set and a List in Java?
41. What is a Map in Java, and can you give an example of a Map implementation?
42. Can you explain the difference between an Iterator and a ListIterator in Java?
43. What is a java.util.Optional, and how can it be used?
44. Can you explain the difference between a Java Bean and a POJO?
45. Can you explain the difference between an Array and an ArrayList in Java?
46. Can you explain the difference between a HashMap and a TreeMap in Java?
47. Can you explain the difference between a LinkedList and a Stack in Java?
48. What is a JavaFX, and how does it differ from Swing in Java?
49. Can you explain the Model-View-Controller (MVC) design pattern in Java?
50. What is a Servlet in Java, and how does it work?
51. Can you explain the difference between a Servlet and a JSP in Java?
52. What is the Java Persistence API (JPA), and how can it be used?
53. Can you explain the difference between a Java Bean and a Java Entity in JPA?
54. Can you explain the difference between a Hibernate Session and a Hibernate EntityManager?
55. What is the Java Transaction API (JTA), and how can it be used?
56. Can you explain the difference between a stateless and a stateful session bean in Java?
57. Can you explain the difference between a Message-Driven Bean (MDB) and a Session Bean in Java?
58. What is the difference between a checked and an unchecked exception in Java?
59. Can you explain the difference between a constructor and a static block in Java?
60. What is the difference between a final and a static variable in Java?
61. Can you explain the difference between a final and a finally block in Java?
62. What is the difference between a for loop and a for-each loop in Java?
63. Can you explain the difference between a static and a non-static method in Java?
64. What is the difference between a private and a protected method in Java?
65. Can you explain the difference between an interface and an abstract class in Java?
66. Can you explain the difference between inheritance and composition in Java?
67. What is the difference between a package and an import statement in Java?
68. Can you explain the difference between a try-with-resources and a try-finally block in Java?
69. What is the difference between a synchronized and a volatile variable in Java?
70. Can you explain the difference between a method overriding and a method overloading in Java?
71. What is the difference between a String and a StringBuffer in Java?
72. Can you explain the difference between a String and a StringBuilder in Java?

These are just a few of the common Java interview questions that you may encounter during a job interview. It’s important to be prepared and have a good understanding of the basic concepts of the Java programming language.