Using inheritance (the "is a" relation). : Inheritance « Object Oriented « SCJP

1. SCJP
2. Object Oriented
3. Inheritance

class Rectangle {
  private int width = 0;

  private int height = 0;

  public void setSize(int w, int h) {
    this.width = w;
    this.height = h;
  }

}

class Window extends Rectangle {
  private String title;

  public void setTitle(String t) {
    this.title = t;
  }
}