Pair { @Override public String toString() { return "<" + first + ", " + second + ">"; } Pair(S first, T second); static DRes<Pair<S, T>> lazy(S first, T second); S getFirst(); T getSecond(); @Override boolean equals(Object obj); @Override String toString(); @Override int hashCode();  }
@Test public void testToString() { Pair<String, Integer> pair1 = new Pair<>("Foo", 5); assertEquals("<Foo, 5>", pair1.toString()); }