Difference between Constructors and Methods in Java

Java Object Oriented Programming Programming

Constructors are special methods used to initialize objects whereas methods are used to execute certain statements. Following are the important differences between Constructors and Methods.

Sr. No.	Key	Constructors	Methods
1	Purpose	Constructor is used to create and initialize an Object .	Method is used to execute certain statements.
2	Invocation	A constructor is invoked implicitly by the System.	A method is to be invoked during program code.
3	Invocation	A constructor is invoked when new keyword is used to create an object.	A method is invoked when it is called.
4	Return type	A constructor can not have any return type.	A method can have a return type.
5	Object	A constructor initializes an object which is not existent.	A method can be invoked only on existing object.
6	Name	A constructor must have same name as that of the class.	A method name can not be same as class name.
7	Inheritance	A constructor cannot be inherited by a subclass.	A method is inherited by a subclass.

Example of Constructor vs Method

JavaTester.java

public class JavaTester {
   int num;
   JavaTester(){
      num = 3;
      System.out.println("Constructor invoked. num: " + num);
   }
   public void init(){
      num = 5;
      System.out.println("Method invoked. num: " + num);
   }
   public static void main(String args[]) {
      JavaTester tester = new JavaTester();
      tester.init();
   }
}

Output

Constructor invoked. num: 3
Method invoked. num: 5

Mahesh Parahar

Published on 26-Nov-2019 10:14:38

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