/**
   * Determines if the given iterable contains no elements.
   *
   * <p>There is no precise {@link Iterator} equivalent to this method, since one can only ask an
   * iterator whether it has any elements <i>remaining</i> (which one does using {@link
   * Iterator#hasNext}).
   *
   * <p><b>{@code Stream} equivalent:</b> {@code !stream.findAny().isPresent()}
   *
   * @return {@code true} if the iterable contains no elements

  }

  /**
   * Returns an immutable sorted set containing the given elements sorted by their natural ordering.
   * When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
   * one specified is included.
   *
   * @throws NullPointerException if any element is null
   */

   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this method is equivalent to Java 8's
   * {@code Optional.ofNullable}.
   */
  public static <T> Optional<T> fromNullable(@CheckForNull T nullableReference) {
    return (nullableReference == null) ? Optional.<T>absent() : new Present<T>(nullableReference);
  }

  /**
   * Returns the equivalent {@code com.google.common.base.Optional} value to the given {@code

   * algorithm, x86 variant</a> (little-endian variant), using the given seed value, <b>with a known
   * bug</b> as described in the deprecation text.
   *
   * <p>The C++ equivalent is the MurmurHash3_x86_32 function (Murmur3A), which however does not
   * have the bug.
   *
   * @deprecated This implementation produces incorrect hash values from the {@link

   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()
   *         .put('b', "anana")
   *         .putAll('a', "pple", "sparagus")

  }

  /**
   * Returns an immutable sorted set containing the given elements sorted by their natural ordering.
   * When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
   * one specified is included.
   *
   * @throws NullPointerException if any element is null
   */

     * and Equivalence<Object>.
     */
    private final Equivalence<? super @NonNull T> equivalence;

    @ParametricNullness private final T reference;

    private Wrapper(Equivalence<? super @NonNull T> equivalence, @ParametricNullness T reference) {
      this.equivalence = checkNotNull(equivalence);
      this.reference = reference;
    }

     * and Equivalence<Object>.
     */
    private final Equivalence<? super @NonNull T> equivalence;

    @ParametricNullness private final T reference;

    private Wrapper(Equivalence<? super @NonNull T> equivalence, @ParametricNullness T reference) {
      this.equivalence = checkNotNull(equivalence);
      this.reference = reference;
    }

   *     however, that passing an explicit {@code null} cause prevents anyone from calling {@link
   *     #initCause} later, so it is not quite equivalent to using a constructor that omits the
   *     cause.
   */
  @Deprecated
  protected ExecutionError() {}

  /**
   * Creates a new instance with the given detail message and no cause.
   *

   * implicit).
   */
  protected Ordering() {}

  // Instance-based factories (and any static equivalents)

  /**
   * Returns the reverse of this ordering; the {@code Ordering} equivalent to {@link
   * Collections#reverseOrder(Comparator)}.
   *
   * <p><b>Java 8+ users:</b> Use {@code thisComparator.reversed()} instead.
   */