How to use this keyword in java

The keyword this is useful when you need to refer to instance of the class from its method. The keyword helps us to avoid name conflicts. As we can see in the program that we have declare the name of instance variable and local variables same. Now to avoid the confliction between them we use this keyword. Here, this section provides you an example with the complete code of the program for the illustration of how to what is this keyword and how to use it.

In the example, this.length and this.breadth refers to the instance variable length and breadth while length and breadth refers to the arguments passed in the method. We have made a program over this. After going through it you can better understand.

Here is the code of the program:

class Rectangle{
int length,breadth;
void show(int length,int breadth){
  this.length=length;
  this.breadth=breadth;
}
int calculate(){
  return(length*breadth);
}
}
public class UseOfThisOperator{
public static void main(String[] args){
  Rectangle rectangle=new Rectangle();
  rectangle.show(5,6);
  int area = rectangle.calculate();
  System.out.println("The area of a Rectangle is  :  " + area);
}
}

Output of the program is given below:
C:\java>java UseOfThisOperator
The area of a Rectangle is : 30