code: public static <E1,E2> Collection<E2> mapColl(Iterable<E1> coll, Function<E1,E2> func, Collection<E2> newColl) {
  	for(E1 elem : coll) {
  	    newColl.add(func.f(elem));
  	}
  	return newColl;
      }
docs: Maps collection <code>coll</code> into a new collection
  (stored in <code>newColl</code>), according to the function
  <code>func</code>.