JAVA Constructor Overloading Program Using Object as Parameter

Generally, constructors are used to initialize class member variables. When we use multiple constructors in a class definition, then it is known as constructor overloading. We can use default constructors and parameterized constructors for the overloading. 

But, in this program, I am showing the use of the class's object as a parameter in the constructor. Here the class is Shape, so I am using the object s of the class Shape as the parameter of the last constructor.
When the constructor calls, the s4 object is created with the copy of the s3 object as a parameter. So, the display area method will return the same value for s3 and s4 objects.

class Shape //general class

{
    int side1, side2; //member variables
    Shape() //default constructor [no parameter]
    {
        side1=side2=0;
    }
    Shape(int x) //single parameterized constructor
    {
        side1=side2=x; //initialize with x
    }
    Shape(int x, int y) //double parameterized constructor
    {
        side1=x; side2=y; //initialize with x y
    }
    Shape(Shape s) //single parameterized constructor
    {
        side1=s.side1; //initialize with s object
        side2=s.side2;
    }
    void display_Area() //member method
    {
        System.out.println("Area of the shape ="+(side1*side2));
    }
}
public class MainShape //main class
{
    public static void main(String args[])
    {
        Shape s1 = new Shape(); //1st object create
        s1.display_Area(); //area=0
        Shape s2 = new Shape(5); //2nd object create
        s2.display_Area(); //area=25
        Shape s3 = new Shape(4,6); //3rd object create
        s3.display_Area(); //area=24
        Shape s4=new Shape(s3); //4th object
        s4.display_Area(); //area=24
    }
}

Output:-