class Pair<A,B> {
final A first; final B second;
Pair(A a, B b)
{ this.first = a; this.second = b; }
}
Pair<String,Integer> p =
new Pair<String,Integer>("foo", 42);
int x = p.second + 3;
vor allem für Container-Typen
(Liste, Menge, Keller, Schlange, Baum, ...)