Polymorphism with interface example in Java

//  Polymorphism  with interface example
interface Shape
{
void draw();
}
class Rectangle implements Shape
{
public void draw()
{
 System.out.println("Drawing Rectangle.");
}
}
class Triangle implements Shape
{
public void draw()
{
 System.out.println("Drawing Triangle.");
}
}

class  PolymorphismTest8 
{
public static void main( String args[ ] )
{
 Shape s;
 
 Rectangle r = new Rectangle();
 s = r;
 s.draw();
 
 Triangle t = new Triangle();
 s = t;
 s.draw();
}
}

Output:
Drawing Rectangle.
Drawing Triangle.