Passing a Reference Variable

Passing a Reference Variable :
When you pass a reference variables to a method ,you pass a copy of the passed reference variables .Both references points to the same object

Note : Both references can change a member in the object .

Example :

Code:

public class Main {

     
           
    public static void main(String[] args) {
       
          Main test=new Main();
          circle newc=new circle();
          newc.setR(43);
          System.out.println("Before calling method : R="+newc.getR());
          test.changeR(newc);
          System.out.println("After calling method : R="+newc.getR());
         
    }
    public void changeR(circle c)
           
    {
        c.setR(32);
        c=null;
    }
}

interface shape
{
     
     public void Draw();
     
     
}
class circle implements shape
{
    private int R;
    public void Draw() {
        System.out.println("Drawing Circle here");
    }

    public void setR(int R) {
        this.R = R;
    }

    public int getR() {
        return R;
    }
   
     
     
}

The result :

Code:

Before calling method : R=43
After calling method : R=32