Lecture 7 - slide 38 : 41

// illustration af covariant problematik i Java

class S {
  private String s;

  public S(){s = "S";}

  public void sOp(){
    System.out.println("sOp i S");
    s = s + s;
  }

}

class T extends S {
  private String t;

  public T(){t = "T";}
 
  public void tOp(){
    System.out.println("tOp i T");
    t = t + t;
  }
}

class A {
 private String v;

 public A(){v = "A";}

 void meth(S p){
   System.out.println("meth i A");
   p.sOp();
 }

}

class B extends A{

 private String v;

 public B(){v = "B";}

 void meth(T p){
   System.out.println("meth i B");
   p.tOp();
 }
}


class RedefTry1 {

 public static void main (String[] args){
 
   A aref;
   B bref = new B();
   S sref = new S();

   aref = bref;

   aref.meth(sref);

 }

}