class BodyOfA extends A { 
   BodyOfA  
  
  public BodyOfA(A h) { super(911); handle = h; }
  
  public void f1() { System.out.println("A.f1"); handle.f2(); }
  public void f2() { System.out.println("A.f2"); }
  
  A handle;   
 reference to invocation context
  };