}

  @AndroidIncompatible // Presumably GC doesn't trigger, despite our efforts.
  public void testWeakImplementations() {
    for (Striped<?> striped : weakImplementations()) {
      WeakReference<Object> weakRef = new WeakReference<>(striped.get(new Object()));
      GcFinalization.awaitClear(weakRef);
    }
  }

  @AndroidIncompatible // Presumably GC doesn't trigger, despite our efforts.
  public void testWeakReadWrite() {

    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>());

  }

  @AndroidIncompatible // Presumably GC doesn't trigger, despite our efforts.
  public void testWeakImplementations() {
    for (Striped<?> striped : weakImplementations()) {
      WeakReference<Object> weakRef = new WeakReference<>(striped.get(new Object()));
      GcFinalization.awaitClear(weakRef);
    }
  }

  @AndroidIncompatible // Presumably GC doesn't trigger, despite our efforts.
  public void testWeakReadWrite() {

 * 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.
 *

 * 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>This implementation consumes significantly less memory than {@code java.util.LinkedHashSet} or
 * even {@code java.util.HashSet}, and places considerably less load on the garbage collector. Like

   *
   * <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}.
   */

@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
final class LongAddables {
  private static final Supplier<LongAddable> SUPPLIER;

  static {
    Supplier<LongAddable> supplier;
    try {
      // trigger static initialization of the LongAdder class, which may fail
      LongAdder unused = new LongAdder();
      supplier =
          new Supplier<LongAddable>() {
            @Override
            public LongAddable get() {

  }

  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.
 *