69 Core Java Interview Questions (PDF)

Java is one of the most popular and widely used programming languages in the world. Whether you aspire to work as a Java developer or are preparing for a job interview that involves Java, you’ll want to have a strong grasp of core Java concepts.

In this blog post, we’ll go over 69 important Java interview questions that cover fundamental topics like OOP principles,Exception handling, Collections, Generics, String handling, Multithreading and more. Being able to confidently answer these types of questions will help you succeed during the technical part of Java interviews.

Why “69 Core Java Interview Questions”?

In this PDF Post, we have compiled a comprehensive collection of 69 Core Java Interview Questions that are commonly asked in interviews. To make it even more convenient for you, we have made these programs available in a downloadable PDF format.

69 Core Java Interview Questions

Let’s get started!

1. what are static blocks and static initalizers in Java ?
2. How to call one constructor from the other constructor ?
3. What is method overriding in java ?
4. What is super keyword in java ?
5. Difference between method overloading and method overriding in java ?
6. Difference between abstract class and interface ?
7. Why java is platform independent?
8. What is method overloading in java ?
9. What is difference between c++ and Java ?
10. What is JIT compiler ?
11. What is bytecode in java ?
12. Difference between this() and super() in java ?
13. What is a class ?
14. What is an object ?
15. What is method in java ?
16. What is encapsulation
17. Why main() method is public, static and void in java ?
18. Explain about main() method in java ?
19. What is constructor in java ?
20. What is difference between length and length() method in java ?
21. What is ASCII Code?
22. What is Unicode ?
23. Difference between Character Constant and String Constant in java ?
24. What are constants and how to create constants in java?
25. Difference between ‘>>’ and ‘>>>’ operators in java?
26. Explain Java Coding Standards for classes or Java coding conventions for classes?
27. Explain Java Coding standards for interfaces?
28. Explain Java Coding standards for Methods?
29. Explain Java Coding Standards for variables ?
30. Explain Java Coding Standards for Constants?
31. Difference between overriding and overloading in java?
32. What is ‘IS-A ‘ relationship in java?
33. Difference between ‘IS-A’ and ‘HAS-A’ relationship in java?
34. Explain about instanceof operator in java?
35. What does null mean in java?
36. Can we have multiple classes in single file ?
37. What all access modifiers are allowed for top class ?
38. What are packages in java?
39. Can we have more than one package statement in source file ?
40. Can we define package statement after import statement in java?
41. What are identifiers in java?
42. What are access modifiers in java?
43. What is the difference between access specifiers and access modifiers in java?
44. What access modifiers can be used for class ?
45. Explain what access modifiers can be used for methods?
46. Explain what access modifiers can be used for variables?
47. What is final access modifier in java?
48. Explain about abstract classes in java?
49. Can we create constructor in abstract class ?
50. What are abstract methods in java?
51. What is an exception in java?
52. State some situations where exceptions may arise in java?
53. What is Exception handling in java?
54. What is an eror in Java?
55. What are advantages of Exception handling in java?
56. In how many ways we can do exception handling in java?
57. List out five keywords related to Exception handling ?
58. Explain try and catch keywords in java?
59. Can we have try block without catch block?
60. Can we have multiple catch block for a try block?
61. Explain importance of finally block in java?
62. Can we have any code between try and catch blocks?
63. Can we have any code between try and finally blocks?
64. Can we catch more than one exception in single catch block?
65. What are checked Exceptions?
66. What are unchecked exceptions in java?
67. Explain differences between checked and Unchecked exceptions in java?
68. What is default Exception handling in java?

Conclusion

I hope these core Java interview questions help you assess your current knowledge and identify areas for improvement. Being able to confidently answer such basic questions will help you clear Java technical rounds. Let me know if you need any clarification on specific questions. Happy learning!

Nu Of Pages

12 Pages

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