assertThrows(IllegalStateException.class, () -> builder2.softValues());
    assertThrows(IllegalStateException.class, () -> builder2.weakValues());
  }

  @GwtIncompatible // Duration
  public void testLargeDurationsAreOk() {
    Duration threeHundredYears = Duration.ofDays(365 * 300);
    CacheBuilder<Object, Object> unused =
        CacheBuilder.newBuilder()
            .expireAfterWrite(threeHundredYears)