35 Java Interview Questions for Freshers and Experienced

If you are preparing for a Java interview or looking job opportunity in Java development, here are the 35 Java interview questions you must prepare for.

Whether you are a fresher or experienced candidate, going through this list will help you test your preparation before actually heading to the interview.

Java Interview Questions 2023

Check it out…

1. What are the features and characteristics of Java?
2. Why Java doesn’t support multiple inheritances?
3. Why Java is not a pure Object Oriented language?
   Answer: Java is an object-oriented language but not a purely object-oriented language. Read the detail here.
4. How to sort a collection of custom Objects in Java?
5. Difference between Java JRE, JDK and JVM.
6. Java Compiler is stored in JDK, JRE or JVM?
7. What do System.gc() and Runtime.gc() methods do?
8. Explain Java operators.
9. What is Application Context?
10. What is JDBC?
11. What is Busy Spinning? Why Should You Use It in Java?
12. How to Make an Object Immutable in Java? Why Should You Make an ObjectImmutable?
13. Do you know about Open Closed Design Principle or Liskov Substitution Principle?
14. Which Two Methods HashMap Key Object Should Implement?
15. How do you share an object between threads? or How to pass an object from one thread to another?
16. What is the difference between imperative and declarative programming paradigms?
17. Does functional programming use an imperative or declarative approach?
18. What is the difference between throw and throws in Java exceptions?
19. Where does FP shine?
20. What is the difference between method overloading and overriding?
21. Does the constructor return any value?
22. Is the constructor inherited?
23. Can you make a constructor final?
24. Can we overload the constructors?
    Answer: Yes. Read Java constructor and overloading.
25. What is the static block?
26. Can we override the static methods?
27. Can we execute a program without main() method?
28. What if the static modifier is removed from the signature of the main method?
29. Can we make constructors static?
30. Can we make the abstract methods static in Java?
31. Can we declare the static variables and methods in an abstract class?
32. What are the main uses of the super keyword?
33. What are the differences between this and the super keyword?
34. What is the difference between Java Applet and Application?
35. What is the difference between HashMap and HashSet in Java?

Along with these theoretical Java interview questions, the interviewer can ask you Java coding questions. Practice solving them.

If you have any doubt, ask me in the comment section below. Also, share your interview experience so that it will help other job aspirants.

All the best!

Aniruddha Chaudhari

I am a Python enthusiast who loves Linux and Vim. I hold a Master of Computer Science degree from NIT Trichy and have 10 years of experience in the IT industry, focusing on the Software Development Lifecycle from Requirements Gathering, Design, Development to Deployment. I have worked at IBM, Ericsson, and NetApp, and I share my knowledge on CSEstack.org.