Point et ColorPoint in Java 

class Point extends Object {
        protected int x;
        void setx(int x) { this.x = x;}
        int  getx() { return x;}
}

class ColorPoint extends Point {
        protected String c;
        void setx(String c) { this.c = c.clone();}
        String getcol() { return c;}
}

  Point p;
  ColorPoint q;

  p.setx(3);
  q.setx(4);
  q.setcol("blue");
  System.out.println("Point at "
                     +p.getx().toString()
                     +" "+q.getcol()
                     +" Colorpoint at "
                     +q.getx().toString()
                     +"\n");;