assertEquals("[]", new AtomicDoubleArray(0).toString());
    assertEquals("[]", new AtomicDoubleArray(new double[0]).toString());
  }

  /** compareAndSet treats +0.0 and -0.0 as distinct values */
  public void testDistinctZeros() {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);
    for (int i : new int[] {0, SIZE - 1}) {
      assertFalse(aa.compareAndSet(i, -0.0, 7.0));

  /**
   * Null ('\0'): The all-zeros character which may serve to accomplish time fill and media fill.
   * Normally used as a C string terminator.
   *
   * <p>Although RFC 20 names this as "Null", note that it is distinct from the C/C++ "NULL"
   * pointer.
   *
   * @since 8.0
   */
  public static final byte NUL = 0;

  /**
   * Start of Heading: A communication control character used at the beginning of a sequence of

   * arrays. Like {@code Joiner}, it is thread-safe and immutable.
   *
   * <p>In addition to operating on {@code Map} instances, {@code MapJoiner} can operate on {@code
   * Multimap} entries in two distinct modes:
   *
   * <ul>
   *   <li>To output a separate entry for each key-value pair, pass {@code multimap.entries()} to a
   *       {@code MapJoiner} method that accepts entries as input, and receive output of the form

  }

  @Override
  Spliterator<Cell<R, C, @Nullable V>> cellSpliterator() {
    return CollectSpliterators.<Cell<R, C, @Nullable V>>indexed(
        size(), Spliterator.ORDERED | Spliterator.NONNULL | Spliterator.DISTINCT, this::getCell);
  }

  private Cell<R, C, @Nullable V> getCell(int index) {
    return new Tables.AbstractCell<R, C, @Nullable V>() {
      final int rowIndex = index / columnList.size();

   *
   * <p><b>Warning: do not depend</b> on the behavior of this method.
   *
   * <p>Historically, {@code Equivalence} instances in this library have implemented this method to
   * recognize certain cases where distinct {@code Equivalence} instances would in fact behave
   * identically. However, as code migrates to {@code java.util.function}, that behavior will
   * disappear. It is best not to depend on it.
   */
  @Override

   * arrays. Like {@code Joiner}, it is thread-safe and immutable.
   *
   * <p>In addition to operating on {@code Map} instances, {@code MapJoiner} can operate on {@code
   * Multimap} entries in two distinct modes:
   *
   * <ul>
   *   <li>To output a separate entry for each key-value pair, pass {@code multimap.entries()} to a
   *       {@code MapJoiner} method that accepts entries as input, and receive output of the form

        Object argValue = generate(paramType);
        if (argValue == null) {
          // When a parameter of a @Generates method cannot be created,
          // The type most likely is a collection.
          // Our distinct proxy doesn't work for collections.
          // So just refuse to generate.
          return null;
        }
        args.add(argValue);
      }
      return invokeGeneratorMethod(generate, args.toArray());

 *
 * Usually a webserver is reachable with multiple identifiers: its IP addresses, registered
 * domain names, and even `localhost` when connecting from the server itself. Each of a web server's
 * names is a distinct URL and they are not interchangeable. For example, even if
 * `http://square.github.io/dagger` and `http://google.github.io/dagger` are served by the same IP
 * address, the two URLs identify different resources.
 *

      } else {
        return false;
      }
    }

    @Override
    public int hashCode() {
      return m.hashCode();
    }
  }

  // Test that we should get a distinct parameter error when doing equals test.
  static class ConstructorParameterWithOptionalNotInstantiable {
    public ConstructorParameterWithOptionalNotInstantiable(Optional<NotInstantiable> x) {
      checkNotNull(x);

 * <p>To implement a multimap, a subclass must define the method {@link #createCollection()}, which
 * creates an empty collection of values for a key.
 *
 * <p>The multimap constructor takes a map that has a single entry for each distinct key. When you
 * insert a key-value pair with a key that isn't already in the multimap, {@code
 * AbstractMapBasedMultimap} calls {@link #createCollection()} to create the collection of values