Hi Friend,

Try the following code:

import java.lang.reflect.*;
class rectangle{
    int length,breadth;
    void show(int l,int b){
        this.length=l;
        this.breadth=b; 
        }
        private int calculate(){
            int size;
            size=length*breadth;
            return size;
        }
    }
public class useOfthisoperator {
    public static void main(String args[])throws Exception{ 
        rectangle r=new rectangle();
        r.show(5,6); 
        Method meth = rectangle.class.getDeclaredMethod("calculate");
        meth.setAccessible(true);
        Integer result = (Integer)meth.invoke(r);

System.out.println("Area of rectangle= " + result);
    }
}

Thanks