// ImmutableMap.Builder, so that it can remember any DuplicateKey encountered and produce an
  // exception for a later buildOrThrow(). If builder is null that means that a duplicate
  // key will lead to an immediate exception. If it is not null then a duplicate key will instead be
  // stored in the builder, which may use it to throw an exception later.
  static <K, V> RegularImmutableMap<K, V> create(

@ElementTypesAreNonnullByDefault
public final class SettableFuture<V extends @Nullable Object>
    extends AbstractFuture.TrustedFuture<V> {
  /**
   * Creates a new {@code SettableFuture} that can be completed or cancelled by a later method call.
   */
  public static <V extends @Nullable Object> SettableFuture<V> create() {
    return new SettableFuture<>();
  }

  @CanIgnoreReturnValue
  @Override

  static final ReverseNaturalOrdering INSTANCE = new ReverseNaturalOrdering();

  @Override
  public int compare(Comparable<?> left, Comparable<?> right) {
    checkNotNull(left); // right null is caught later
    if (left == right) {
      return 0;
    }

    return ((Comparable<Object>) right).compareTo(left);
  }

  @Override
  public <S extends Comparable<?>> Ordering<S> reverse() {

    TestQueue<String> inner = new TestQueue<>();
    Queue<String> outer = Synchronized.queue(inner, null);
    inner.mutex = outer;
    outer.add("foo"); // necessary because we try to remove elements later on
    return outer;
  }

  private static final class TestQueue<E> implements Queue<E> {
    private final Queue<E> delegate = Lists.newLinkedList();
    public Object mutex;

    @Override

How to contribute
=================

Thank you so much for wanting to contribute to Guava! Here are a few important
things you should know about contributing:

1.  API changes require discussion, use cases, etc. Code comes later.
2.  Pull requests are great for small fixes for bugs, documentation, etc.
3.  Pull requests are not merged directly into the master branch.
4.  Code contributions require signing a Google CLA.

API changes
-----------

    // A second pass will retain only the first entry for that key, but with this last value. The
    // value will then be replaced by null, signaling that later entries with the same key should
    // be deleted.
    Map<K, @Nullable V> duplicates = null;
    int dupCount = 0;
    for (int i = 0; i < n; i++) {

  /** The first exception encountered if any threadAssertXXX method fails. */
  private final AtomicReference<Throwable> threadFailure = new AtomicReference<>(null);

  /**
   * Records an exception so that it can be rethrown later in the test harness thread, triggering a
   * test case failure. Only the first failure is recorded; subsequent calls to this method from
   * within the same test have no effect.
   */

            deltaToCeiling++;
          }

          int diff = Longs.compare(deltaToFloor, deltaToCeiling);
          if (diff < 0) { // closer to floor
            return roundFloorAsDouble;
          } else if (diff > 0) { // closer to ceiling
            return roundCeilingAsDouble;
          }
          // halfway between the representable values; do the half-whatever logic

    }
  }

  /**
   * On a concurrent computation that returns null, all threads should get an
   * InvalidCacheLoadException, with the loader only called once. The result should not be cached (a
   * later request should call the loader again).
   */
  private static void testConcurrentLoadingNull(CacheBuilder<Object, Object> builder)
      throws InterruptedException {

    int count = 10;

    /**
     * Constructs a new iterator over all values for the specified key starting at the specified
     * index. This constructor is optimized so that it starts at either the head or the tail,
     * depending on which is closer to the specified index. This allows adds to the tail to be done
     * in constant time.
     *
     * @throws IndexOutOfBoundsException if index is invalid
     */