barrier.await(1, SECONDS);

                        // WAIT #2
                        barrier.await(1, SECONDS);
                        assertTrue(executor.isShutdown());
                        assertFalse(executor.isTerminated());

                        // WAIT #3
                        barrier.await(1, SECONDS);
                        return null;
                      });

    @Keep public static final WithPublicConstants SECOND = new WithPublicConstants();
  }

  private static class FirstConstantIsNull {
    // To test that null constant is ignored
    @Keep public static final @Nullable FirstConstantIsNull FIRST = null;

    @Keep public static final FirstConstantIsNull SECOND = new FirstConstantIsNull();
  }

  public static class NonFinalFieldIgnored {

    runLatch.await();
    taskLatch.countDown();

    ExecutionException e = assertThrows(ExecutionException.class, () -> task.get(5, SECONDS));
    assertThat(e).hasCauseThat().isInstanceOf(IllegalStateException.class);

    assertTrue(listenerLatch.await(5, SECONDS));
    assertTrue(task.isDone());
    assertFalse(task.isCancelled());
  }

        createCacheBuilder().expireAfterWrite(99999, SECONDS),
        createCacheBuilder().maximumSize(SMALL_MAX_SIZE).expireAfterAccess(SMALL_MAX_SIZE, SECONDS),
        createCacheBuilder().maximumSize(SMALL_MAX_SIZE).expireAfterWrite(SMALL_MAX_SIZE, SECONDS));
  }

  /** Returns an iterable containing all combinations weakKeys and weak/softValues. */

     * -2: use system default, -1: never expire, 0 or positive: expire after specified days.
     */
    protected int documentExpires = -2;

    /**
     * Hot thread monitoring interval in seconds.
     * -1: disabled, positive value: enable hot thread monitoring with specified interval.
     * Used for performance analysis and debugging of the crawler process.
     */
    protected int hotThreadInterval = -1;

import static com.google.common.cache.TestingRemovalListeners.queuingRemovalListener;
import static com.google.common.truth.Truth.assertThat;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.cache.CacheLoader.InvalidCacheLoadException;
import com.google.common.cache.TestingRemovalListeners.QueuingRemovalListener;

   * @param second the second array of elements to concatenate
   * @param type the component type of the returned array
   */
  @GwtIncompatible // Array.newInstance(Class, int)
  public static <T extends @Nullable Object> T[] concat(
      T[] first, T[] second, Class<@NonNull T> type) {
    T[] result = newArray(type, first.length + second.length);
    arraycopy(first, 0, result, 0, first.length);

        // Signal all threads to start at once
        startLatch.countDown();

        // Wait for all threads to complete
        assertTrue("Threads did not complete in time", doneLatch.await(5, TimeUnit.SECONDS));

        // All threads should fail with the same IOException (endpoint is blank)
        // But importantly, there should be no race condition errors
        assertEquals(threadCount, failureCount.get());

    // causing the thread to be suspended for 3.5 seconds, and then park itself for 2 seconds after
    // being resumed. To avoid a flake in this scenario, calculate how long that thread actually
    // waited and assert based on that time. Empirically, the race where the thread ends up waiting
    // for 5.5 seconds happens about 2% of the time.

   * concurrent maps whose content may change while the method is running.
   *
   * <p>The serialized output consists of the number of entries, first key, first value, second key,
   * second value, and so on.
   */
  static <K extends @Nullable Object, V extends @Nullable Object> void writeMap(
      Map<K, V> map, ObjectOutputStream stream) throws IOException {
    stream.writeInt(map.size());