// Since this class only needs CAS on one field, we can avoid this bug by extending AtomicReference
// instead of using an AtomicReferenceFieldUpdater. This reference stores Thread instances
// and DONE/INTERRUPTED - they have a common ancestor of Runnable.
abstract class InterruptibleTask<T extends @Nullable Object>
    extends AtomicReference<@Nullable Runnable> implements Runnable {
  static {

import java.util.PriorityQueue;
import java.util.Queue;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A double-ended priority queue, which provides constant-time access to both its least element and
 * its greatest element, as determined by the queue's specified comparator. If no comparator is
 * given at creation time, the natural order of elements is used. If no maximum size is given at

    private static final long serialVersionUID = 0;
  }

  /**
   * Returns a synchronized (thread-safe) navigable set backed by the specified navigable set. In
   * order to guarantee serial access, it is critical that <b>all</b> access to the backing
   * navigable set is accomplished through the returned navigable set (or its views).
   *
   * <p>It is imperative that the user manually synchronize on the returned sorted set when

        Class<?> processHandleInfoClass = Class.forName("java.lang.ProcessHandle$Info");
        Class<?> optionalClass = Class.forName("java.util.Optional");
        /*
         * We don't *need* to use reflection to access Optional: It's available on all JDKs we
         * support, and Android code won't get this far, anyway, because ProcessHandle is
         * unavailable. But given how much other reflection we're using, we might as well use it

   * to determine whether {@code copyOf} implementations should make an explicit copy to avoid
   * memory leaks.
   */
  boolean isPartialView() {
    return map.isPartialView();
  }

  // accessors

  @Override
  public boolean containsKey(@CheckForNull Object key) {
    return map.containsKey(key);
  }

  @Override
  public boolean containsValue(@CheckForNull Object value) {

   * to determine whether {@code copyOf} implementations should make an explicit copy to avoid
   * memory leaks.
   */
  boolean isPartialView() {
    return map.isPartialView();
  }

  // accessors

  @Override
  public boolean containsKey(@CheckForNull Object key) {
    return map.containsKey(key);
  }

  @Override
  public boolean containsValue(@CheckForNull Object value) {

   * suitable for testing that map entries cannot be modified via a nefarious implementation of
   * equals. This is used for testing unmodifiable collections of map entries; for example, it
   * should not be possible to access the raw (modifiable) map entry via a nefarious equals method.
   */
  public static <K extends @Nullable Object, V extends @Nullable Object>
      Entry<K, V> nefariousMapEntry(K key, V value) {
    return new Entry<K, V>() {

 */
@GwtIncompatible // not worth using in GWT for now
@ElementTypesAreNonnullByDefault
class CompactHashSet<E extends @Nullable Object> extends AbstractSet<E> implements Serializable {
  // TODO(user): cache all field accesses in local vars

  /** Creates an empty {@code CompactHashSet} instance. */
  public static <E extends @Nullable Object> CompactHashSet<E> create() {
    return new CompactHashSet<>();
  }

  /**

   * higher than performing just the operation without enforcing the capacity constraint.
   *
   * This implementation uses a per-segment queue to record a memento of the additions, removals,
   * and accesses that were performed on the map. The queue is drained on writes and when it exceeds
   * its capacity threshold.
   *
   * The Least Recently Used page replacement algorithm was chosen due to its simplicity, high hit

          }
        },
        directExecutor());
    return future;
  }

  /**
   * Returns a default thread factory used to create new threads.
   *
   * <p>When running on AppEngine with access to <a
   * href="https://cloud.google.com/appengine/docs/standard/java/javadoc/">AppEngine legacy
   * APIs</a>, this method returns {@code ThreadManager.currentRequestThreadFactory()}. Otherwise,