this.delegate = delegate;
    this.validator = validator;
    this.errorMessage = errorMessage;
  }

  // Override hashCode() to access delegate directly (so that it doesn't trigger the validate() call
  // via delegate()); it seems inappropriate to throw ISE on this method.
  @Override
  public int hashCode() {
    return delegate.hashCode();
  }

  private void validate() {

    /*
     * TODO: cpovirk - Pre-size the HashMap based on the number of enum values? (But *not* based on
     * the number of entries in the map, as that makes it easy for hostile inputs to trigger lots of
     * allocation—not that any program should be deserializing hostile inputs to begin with!)
     */
    setDelegates(new EnumMap<K, V>(keyTypeOrObjectUnderJ2cl), new HashMap<V, K>());

          @Override
          void afterRanInterruptiblyFailure(Throwable error) {}
        };
    Thread runner = new Thread(task, "runner");
    runner.start();
    isInterruptibleRegistered.await();
    // trigger the interrupt on another thread since it will block
    Thread interrupter =
        new Thread("Interrupter") {
          @Override
          public void run() {
            task.interruptTask();
          }

      iterator.next();
      fail("Expected ConcurrentModificationException");
    } catch (ConcurrentModificationException expected) {
      // success
    }
  }

  /** Trigger the {@code other.size() >= this.size()} case in {@link AbstractSet#removeAll}. */
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)

          @Override
          void afterRanInterruptiblyFailure(Throwable error) {}
        };
    Thread runner = new Thread(task, "runner");
    runner.start();
    isInterruptibleRegistered.await();
    // trigger the interrupt on another thread since it will block
    Thread interrupter =
        new Thread("Interrupter") {
          @Override
          public void run() {
            task.interruptTask();
          }

   *
   * <p>Currently, this method is invoked while holding a lock. If an implementation of this method
   * blocks, it can prevent this service from changing state. If you need to performing a blocking
   * operation in order to trigger shutdown, consider instead registering a listener and
   * implementing {@code stopping}. Note, however, that {@code stopping} does not run at exactly the
   * same times as {@code triggerShutdown}.
   */

  }

  private static Set<Feature<?>> computeKeySetFeatures(Set<Feature<?>> mapFeatures) {
    Set<Feature<?>> keySetFeatures = computeCommonDerivedCollectionFeatures(mapFeatures);

    // TODO(lowasser): make this trigger only if the map is a submap
    // currently, the KeySetGenerator won't work properly for a subset of a keyset of a submap
    keySetFeatures.add(CollectionFeature.SUBSET_VIEW);

 * function doing a good job of distributing the elements to the buckets to a distribution not far
 * from uniform), and amortized since some operations can trigger a hash table resize.
 *
 * <p>As compared with {@link java.util.LinkedHashMap}, this structure places significantly reduced
 * load on the garbage collector by only using a constant number of internal objects.
 *

    this.delegate = delegate;
    this.validator = validator;
    this.errorMessage = errorMessage;
  }

  // Override hashCode() to access delegate directly (so that it doesn't trigger the validate() call
  // via delegate()); it seems inappropriate to throw ISE on this method.
  @Override
  public int hashCode() {
    return delegate.hashCode();
  }

  private void validate() {

   * map built by MapMaker) no longer has a strong reference to this object, the garbage collector
   * will reclaim it and enqueue the phantom reference. The enqueued reference will trigger the
   * Finalizer to stop.
   *
   * If this library is loaded in the system class loader, FinalizableReferenceQueue can load
   * Finalizer directly with no problems.
   *