* concurrency, and performance characteristics as the backing map. In essence, this factory
   * method provides a {@link Set} implementation corresponding to any {@link Map} implementation.
   * There is no need to use this method on a {@link Map} implementation that already has a
   * corresponding {@link Set} implementation (such as {@link java.util.HashMap} or {@link
   * java.util.TreeMap}).
   *

  /*
   * This class is used to serialize all ImmutableSortedSet instances,
   * regardless of implementation type. It captures their "logical contents"
   * only. This is necessary to ensure that the existence of a particular
   * implementation type is an implementation detail.
   */
  @J2ktIncompatible // serialization
  private static class SerializedForm<E> implements Serializable {

      // Some Android 5.0.x Samsung devices have bugs in JDK reflection APIs that cause
      // getDeclaredField to throw a NoSuchFieldException when the field is definitely there.
      // For these users fallback to a suboptimal implementation, based on synchronized. This will
      // be a definite performance hit to those users.
      thrownReflectionFailure = reflectionFailure;
      helper = new SynchronizedAtomicHelper();
    }
    ATOMIC_HELPER = helper;

    checkPositionIndex(index, size());
    if (isEmpty()) {
      return (UnmodifiableListIterator<E>) EMPTY_ITR;
    } else {
      return new Itr<E>(this, index);
    }
  }

  /** A singleton implementation of iterator() for the empty ImmutableList. */
  private static final UnmodifiableListIterator<Object> EMPTY_ITR =
      new Itr<Object>(RegularImmutableList.EMPTY, 0);

   *
   * Other contributors include Andrew Wright, Jeffrey Hayes, Pat Fisher, Mike Judd.
   */

  /**
   * An implementation of {@link ExecutorService#invokeAny} for {@link ListeningExecutorService}
   * implementations.
   */
  @J2ktIncompatible
  @GwtIncompatible
  @ParametricNullness
  static <T extends @Nullable Object> T invokeAnyImpl(

   *       </ul>
   *   <li>another java.util.Map delegate implementation. In most modern JDKs, normal java.util hash
   *       collections intelligently fall back to a binary search tree if hash table collisions are
   *       detected. Rather than going to all the trouble of reimplementing this ourselves, we
   *       simply switch over to use the JDK implementation wholesale if probable hash flooding is

    super.tearDown();
  }

  /*
   * TODO(cpovirk): Use FutureSubject once it's part of core Truth. But be wary of using it when I'm
   * really testing a Future implementation (e.g., in the case of immediate*Future()). But it's OK
   * to use in the case of the majority of Futures that are AbstractFutures.
   */

  public void testImmediateFuture() throws Exception {

    super.tearDown();
  }

  /*
   * TODO(cpovirk): Use FutureSubject once it's part of core Truth. But be wary of using it when I'm
   * really testing a Future implementation (e.g., in the case of immediate*Future()). But it's OK
   * to use in the case of the majority of Futures that are AbstractFutures.
   */

  public void testImmediateFuture() throws Exception {

  }

  private void checkHelperVersion(ClassLoader classLoader, String expectedHelperClassName)
      throws Exception {
    // Make sure we are actually running with the expected helper implementation
    Class<?> abstractFutureClass = classLoader.loadClass(AbstractFuture.class.getName());
    Field helperField = abstractFutureClass.getDeclaredField("ATOMIC_HELPER");
    helperField.setAccessible(true);

  }

  private void checkHelperVersion(ClassLoader classLoader, String expectedHelperClassName)
      throws Exception {
    // Make sure we are actually running with the expected helper implementation
    Class<?> abstractFutureClass = classLoader.loadClass(AbstractFuture.class.getName());
    Field helperField = abstractFutureClass.getDeclaredField("ATOMIC_HELPER");
    helperField.setAccessible(true);