Example program for Java supports Run time Polymorphism

class figure

{

            double dim1,dim2;

            figure(double x,double y)

            {

            dim1=x;

            dim2=y;

            }

            double area()

            {

            System.out.println("Area undefined");

            return 0;

            }

}

class rectangle extends figure

{

            rectangle(double a,double b)

            {

            super(a,b);

            }

            double area()

            {

            System.out.println("Rectangle Area");

            return dim1*dim2;

            }

}

class triangle extends figure

{

            triangle(double x,double y)

            {

            super(x,y);

            }

            double area()

            {

            System.out.println("Triangle Area");

            return dim1*dim2/2;

            }

}

class run

{

            public static void main(String[] args)

            {

            figure obj=new figure(10,10);

            rectangle obj1=new rectangle(9,5);

            triangle obj2=new triangle(10,8);

            figure a;                            //a is a reference of type figure(super class)

            a=obj1;                                   //a refers to object of rectangle(sub class)

            System.out.println("Area="+a.area());

            a=obj;                               //a refers to object of figure

            System.out.println("Area="+a.area());

            a=obj2;                                   //a refers to object of triangle

            System.out.println("Area="+a.area());

            }

}

O/P:    Rectangle Area

            Area=45.0

            Area undefined

            Area=0.0

            Triangle Area

            Area=40.0