}

    @Override
    public int hashCode() {
      return value;
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 5;
  }

  public void testMutableValues() {
    IntHolder holderA = new IntHolder(1);
    IntHolder holderB = new IntHolder(2);
    Map<String, IntHolder> map = ImmutableMap.of("a", holderA, "b", holderB);
    holderA.value = 3;