List list = getList(); // from somewhere, say a list of Person
  Iterator it = list.iterator();
  while(it.hasNext()){
     // the following line makes perfect sense to me,
     // but it causes a compiler error, I'm supposed to write:
     //     Person p = (Person)it.next();
     // my question: Is the compiler helping me or I'm helping the compiler?
     Person p = it.next();


     // now call some method on p.

   }