### Question:
Tuple { @Override public int hashCode() { return Objects.hash(getFirst(), getSecond()); } Tuple(U first, V second); U getFirst(); V getSecond(); @Override boolean equals(Object o); @Override String toString(); @Override int hashCode();  }### Answer:
@Test void tuple_hashCode() { assertEquals(new Tuple<>("a", "b").hashCode(),new Tuple<>("a", "b").hashCode()); assertNotEquals(new Tuple<>("a", "b").hashCode(),new Tuple<>("a", "c").hashCode()); }