Java Interview Questions and Answers for SDET.

 Question 1: -Explain public static void main(String[] arg)

public: - public is an access modifier, which means that this method is accessible by any class.

Static: - static keyword tells that this method can be accessed without creating an instance of the class.

Void: - this main method returns no value.

Main: - it is the name of java's main method.

String arg[]: - The arg is an array of string types. This contains the command line argument that we can pass while running the program.

Question 2:-What is an object and class?

Object: - An object is an instance of a class.

Class: - A class is a template or blueprint from which objects are created.

Question 3: - What is static in java?

The static keyword is a non-access modifier used for methods, class variables, and attributes.

The static keyword in java is used for memory management mainly.

Question 4: - What do you mean by the constructor?

 Constructor:-  Constructor is a special type of method whose name is the same as a class name. Constructor is called when an instance of the class is created

Questions 6:-  Why create a constructor. The main purpose of Constructor?

The purpose of a constructor is to perform initialize the object of a class.

Question 7:- What is different between final finalize and finally?

Final:-  Final is used to apply restrictions on class, method, and variable. a final method can not be overridden and the final class can not be inherited. and also final variable's value can not be changed.

Question 8: - What is array and ArrayList?

Question 9: - What is the platform?

Ans:-  Platform is a software and hardware programs that runs any machine.

Question 10:- What is abstract class?

Question 11:- What are the differences between C++ and Java?

Questions 12: - Why java is platform independent ?

Questions 13: - Which class is a superclass of all classes?

Questions 14:-  What is a JIT compiler ?