return new CompactHashMap<>(expectedSize);
  }

  private static final Object NOT_FOUND = new Object();

  /**
   * Maximum allowed false positive probability of detecting a hash flooding attack given random
   * input.
   */
  @VisibleForTesting(
      )
  static final double HASH_FLOODING_FPP = 0.001;

  /**
   * Maximum allowed length of a hash table bucket before falling back to a j.u.LinkedHashMap-based

    ArbitraryInstances.get(Stopwatch.class).start();
    assertThat(ArbitraryInstances.get(Ticker.class)).isNotNull();
    assertFreshInstanceReturned(Random.class);
    assertEquals(
        ArbitraryInstances.get(Random.class).nextInt(),
        ArbitraryInstances.get(Random.class).nextInt());
  }

  public void testGet_concurrent() {
    assertTrue(ArbitraryInstances.get(BlockingDeque.class).isEmpty());

    return new CompactHashMap<>(expectedSize);
  }

  private static final Object NOT_FOUND = new Object();

  /**
   * Maximum allowed false positive probability of detecting a hash flooding attack given random
   * input.
   */
  @VisibleForTesting(
      )
  static final double HASH_FLOODING_FPP = 0.001;

  /**
   * Maximum allowed length of a hash table bucket before falling back to a j.u.LinkedHashMap-based

    ArbitraryInstances.get(Stopwatch.class).start();
    assertThat(ArbitraryInstances.get(Ticker.class)).isNotNull();
    assertFreshInstanceReturned(Random.class);
    assertEquals(
        ArbitraryInstances.get(Random.class).nextInt(),
        ArbitraryInstances.get(Random.class).nextInt());
  }

  public void testGet_concurrent() {
    assertTrue(ArbitraryInstances.get(BlockingDeque.class).isEmpty());

                synchronized (this) {
                    ltime = System.currentTimeMillis();
                    wait();
                }

                try {
                    final double r = Math.random();
                    if (r < 0.333) {
                        f.exists();
                        //                      System.out.print('e');
                    } else if (r < 0.667) {

   * only when the resulting list may need further modification, or may contain {@code null}. The
   * input is not modified. The returned list is serializable and has random access.
   *
   * <p>Unlike {@link Sets#newTreeSet(Iterable)}, this method does not discard elements that are
   * duplicates according to the comparator. The sort performed is <i>stable</i>, meaning that such

@defaultMessage Use org.elasticsearch.common.Randomness#get for reproducible sources of randomness
java.util.Random#<init>()
java.util.concurrent.ThreadLocalRandom

java.security.MessageDigest#clone() @ use org.elasticsearch.common.hash.MessageDigests

@defaultMessage Don't use MethodHandles in slow ways, don't be lenient in tests.

        totalSize++;
        if (wasEmpty) {
          addToMap();
        }
      }
    }
  }

  /**
   * List decorator that stays in sync with the multimap values for a key and supports rapid random
   * access.
   */
  private final class RandomAccessWrappedList extends WrappedList implements RandomAccess {
    RandomAccessWrappedList(

   * only when the resulting list may need further modification, or may contain {@code null}. The
   * input is not modified. The returned list is serializable and has random access.
   *
   * <p>Unlike {@link Sets#newTreeSet(Iterable)}, this method does not discard elements that are
   * duplicates according to the comparator. The sort performed is <i>stable</i>, meaning that such

  }

  private static <T extends @Nullable Object> boolean removeIfFromRandomAccessList(
      List<T> list, Predicate<? super T> predicate) {
    // Note: Not all random access lists support set(). Additionally, it's possible
    // for a list to reject setting an element, such as when the list does not permit
    // duplicate elements. For both of those cases,  we need to fall back to a slower