Core java Interview Questions

Here are the Core Java Interview Questions that can be asked to you by interviewers. These frequently asked Core Java Interview Questions will be beneficial to software developers going for Java developer Interviews.

Core java Interview Questions


Here are the Core Java Interview Questions that can be asked to you by interviewers. These frequently asked Core Java Interview Questions will be beneficial to software developers going for Java developer Interviews.

Q 1. Difference between JDK, JRE and JVM?

JVM stands for Java Virtual Machine that provides runtime environment in which java bytecode can be executed. JVM is platform dependent and is responsible for garbage collection, array bounds and checking. JVM is independent from hardware and operating system.

JRE stands for Java Runtime Environment, which comprises of JVM and class libraries. However compiler and debugger are not included in it. JRE is a must in system if one wants to run a Java file.

JRE executes Java files.

JDK stands for Java Development Kit that has both developer tools like compiler, Java application launcher Appletviewer and JRE to run the programs.

JDK is required for programmers who write their own programs

Compiler converts java code into byte code. Java application launcher opens a JRE, loads the class, and invokes its main method.

JDK is for java development.

Q 2. What is an interface in java?

Interface in Java is the collection of methods with empty implementations and constants variables. Methods in an Interface are public and abstract. Implement keyword is used to define methods.

Q 3. What is the Purpose of finalization?

Finalization() method cleans up memory of an object before Garbage Collector cleans it. It is an arbitrary method that contains arbitrary code.

Q 4. What is the garbage collection in Java?

Garbage collection is provided by JVM (Java Virtual Machine) to clean the heap space from objects. Garbage collection is carried out by Garbage collector. Garbage collection is invoked automatically by JVM.

Q 5. Difference between abstract class and interface in java?

  • Method and members of an abstract class can be defined as private, protected, etc while methods of an interface are public by default.
  • Sub-class of an abstract class must define abstract methods while Interface can be extended to another interface without defining the method.
  • Interface is a form of multiple inheritance while an abstract class can be extended to one other class.

Q 6. What is Jagged Arrays in java?

Jagged Array in Java is a new feature. It is an array of arrays. It is used when you have a non-uniform array as you can serialize a data to save it.

Tutorials

  1. Core Java Interview Question Page 1
  2. Core Java Interview Question Page 3
  3. Core Java Interview Question Page 8
  4. Core Java Interview Question, Interview Question
  5. Core Java Interview Question, Interview Question
  6. Core Java Interview Question, Interview Question
  7. Core Java Interview Question, Interview Question
  8. Core Java Interview Question, Interview Question
  9. Core Java Interview Question, Interview Question
  10. Core Java Interview questions and answers
  11. Core Java Interview Question, Interview Question
  12. Core Java Interview Question, Interview Question
  13. Core Java Interview Question, Interview Question
  14. Core Java Interview Question, Interview Question
  15. Core Java Interview Question, Interview Question
  16. Core Java Interview Question, Interview Question
  17. Core Java Interview Question, Interview Question
  18. Core Java Interview Question, Interview Question
  19. Core Java Interview Question, Interview Question
  20. Core Java Interview Question, Interview Question
  21. Core Java Interview Question, Interview Question
  22. Core Java Interview Question, Interview Question
  23. Core Java Interview Question, Interview Question
  24. Core Java Interview Question, Interview Question
  25. Core Java Interview Question, Interview Question
  26. Core Java Interview Question, Interview Question
  27. Core Java Interview Question, Interview Question
  28. Core Java Interview Question, Interview Question
  29. Core Java Interview Question, Interview Question
  30. Core Java Interview Question, Interview Question
  31. Core Java Interview Question, Interview Question
  32. Core Java Interview Question, Interview Question
  33. Core Java Interview Question, Interview Question
  34. Core Java Interview Question, Interview Question
  35. Core java Interview Questions