assertThrows(IllegalArgumentException.class, () -> builder.refreshAfterWrite(Duration.ZERO));
  }

  @GwtIncompatible // refreshAfterWrite
  public void testRefresh_setTwice() {
    CacheBuilder<Object, Object> builder =
        CacheBuilder.newBuilder().refreshAfterWrite(3600, SECONDS);
    assertThrows(IllegalStateException.class, () -> builder.refreshAfterWrite(3600, SECONDS));
  }

  @GwtIncompatible // Duration

    assertThrows(IllegalArgumentException.class, () -> builder.refreshAfterWrite(Duration.ZERO));
  }

  @GwtIncompatible // refreshAfterWrite
  public void testRefresh_setTwice() {
    CacheBuilder<Object, Object> builder =
        CacheBuilder.newBuilder().refreshAfterWrite(3600, SECONDS);
    assertThrows(IllegalStateException.class, () -> builder.refreshAfterWrite(3600, SECONDS));
  }

  @GwtIncompatible // Duration

  @IgnoreJRERequirement // No more dangerous than wherever the caller got the Duration from
  @CanIgnoreReturnValue
  public CacheBuilder<K, V> refreshAfterWrite(Duration duration) {
    return refreshAfterWrite(toNanosSaturated(duration), NANOSECONDS);
  }

  /**
   * Specifies that active entries are eligible for automatic refresh once a fixed duration has

   * method is called when an existing cache entry is refreshed by {@link
   * CacheBuilder#refreshAfterWrite}, or through a call to {@link LoadingCache#refresh}.
   *
   * <p>This implementation synchronously delegates to {@link #load}. It is recommended that it be
   * overridden with an asynchronous implementation when using {@link
   * CacheBuilder#refreshAfterWrite}.
   *

          }
        };

    LoadingCache<Object, Object> cache =
        CacheBuilder.newBuilder()
            .recordStats()
            .ticker(ticker)
            .refreshAfterWrite(1, MILLISECONDS)
            .build(loader);
    Object key = new Object();
    CacheStats stats = cache.stats();
    assertEquals(0, stats.missCount());
    assertEquals(0, stats.loadSuccessCount());

  }

  public void testSetRefresh() {
    long duration = 42;
    TimeUnit unit = SECONDS;
    LocalCache<Object, Object> map =
        makeLocalCache(createCacheBuilder().refreshAfterWrite(duration, unit));
    assertEquals(unit.toNanos(duration), map.refreshNanos);
  }

  public void testLongAsyncRefresh() throws Exception {
    FakeTicker ticker = new FakeTicker();