Top 30 most asked Core Java Questions in Interviews.

Reference : Core Java

1. What is Java? Explain its features.

2. What is the difference between JDK, JRE, and JVM?

3. Explain the concept of OOP and its principles.

4. What is a class and an object in Java?

5. What is the difference between an interface and an abstract class?

6. Explain the concept of inheritance in Java.

7. What is method overloading and method overriding?

8. What is the difference between ‘==’ and ‘equals()’ method?

9. What are constructors in Java?

10. What is the purpose of the final keyword in Java?

11. What are the different data types in Java?

12. What is the difference between int and Integer?

13. Explain the use of the static keyword in Java.

14. What are wrapper classes in Java?

15. What is type casting in Java?

16. Explain the difference between if-else and switch statements.

17. What is a loop? Explain the different types of loops in Java.

18. How does the break statement work in loops?

19. What is the use of the continue statement?

20. Explain the concept of exception handling in Java.

21. What are the different types of collections in Java?

22. Explain the difference between ArrayList and LinkedList.

23. What is a HashMap and how does it work?

24. What are generics in Java?

25. How does a Set differ from a List?

26. What is multithreading in Java?

27. Explain the lifecycle of a thread in Java.

28. What is the difference between Runnable and Thread?

29. What is synchronization and why is it important?

30. Explain the concept of garbage collection in Java.

Other References :
Java8 : Link
Advance Java : Link
Core Java : Link
Java OOP's : Link
Spring Boot : Link
Advanced Spring Boot : Link
Linux : Link
ReactJS : Link
API : Link
OS : Link
NodeJS : Link
Python : Link
HTML : Link