Preconditions.checkNotNull(runnable, "Runnable was null.");
      Preconditions.checkNotNull(executor, "Executor was null.");

      synchronized (this) {
        if (!executed) {
          RunnableExecutorPair newTail = new RunnableExecutorPair(runnable, executor);
          if (head == null) {
            head = newTail;
            tail = newTail;
          } else {

      return spliterator.tryAdvance(action);
    }

    @Override
    @Nullable GeneralSpliterator<E> trySplit() {
      Spliterator<E> split = spliterator.trySplit();
      return split == null ? null : new GeneralSpliteratorOfObject<>(split);
    }
  }

  private static final class GeneralSpliteratorOfPrimitive<
          E extends @Nullable Object, C, S extends Spliterator.OfPrimitive<E, C, S>>

      return spliterator.tryAdvance(action);
    }

    @Override
    @Nullable GeneralSpliterator<E> trySplit() {
      Spliterator<E> split = spliterator.trySplit();
      return split == null ? null : new GeneralSpliteratorOfObject<>(split);
    }
  }

  @IgnoreJRERequirement // *should* be redundant with the annotation on SpliteratorTester
  private static final class GeneralSpliteratorOfPrimitive<

        AndArtifactFilter filter1 = new AndArtifactFilter();

        AndArtifactFilter filter2 = new AndArtifactFilter(Arrays.asList(newSubFilter()));

        assertFalse(filter1.equals(null), "Expected " + filter1 + " to not equal " + null);
        assertTrue(filter1.equals(filter1), "Expected " + filter1 + " to equal " + filter1);
        assertEquals(filter1.hashCode(), filter1.hashCode());

        Objects.requireNonNull(model, "model cannot be null");

        try (Writer out = output) {
            new MavenXpp3Writer().write(out, model);
        }
    }

    @Override
    public void write(OutputStream output, Map<String, Object> options, Model model) throws IOException {
        Objects.requireNonNull(output, "output cannot be null");

      super(toCopy);
      this.hashTable = (toCopy.hashTable == null) ? null : toCopy.hashTable.clone();
      this.maxRunBeforeFallback = toCopy.maxRunBeforeFallback;
      this.expandTableThreshold = toCopy.expandTableThreshold;
      this.hashCode = toCopy.hashCode;
    }

    @Override
    SetBuilderImpl<E> add(E e) {
      checkNotNull(e);
      if (hashTable == null) {
        if (distinct == 0) {

        for (int i = 0; i < l; ++i) {
            Object arg = args[i];
            // if we are careful down below, a null argument goes in there
            // so we can know that the null was passed to the method
            classes[i] = arg == null ? null : arg.getClass();
        }

        return getMostSpecific(methodList, classes);
    }

    /**

  @JvmField val clientMaxWindowBits: Int? = null,
  /** True if the agreed upon extension parameters includes "client_no_context_takeover". */
  @JvmField val clientNoContextTakeover: Boolean = false,
  /** Should be a value in [8..15]. Any value in that range is acceptable by OkHttp. */
  @JvmField val serverMaxWindowBits: Int? = null,

     *
     * @param groupId The group identifier of the POM, must not be {@code null}.
     * @param artifactId The artifact identifier of the POM, must not be {@code null}.
     * @param version The version of the POM, must not be {@code null}.
     * @return The source of the requested POM, never {@code null}.
     * @throws UnresolvableModelException If the POM could not be resolved from any configured repository.
     */

    notEqualObject1 = new ValidTestObject(0, 2);
  }

  /** Test null reference yields error */
  public void testAddNullReference() {
    assertThrows(NullPointerException.class, () -> equalsTester.addEqualityGroup((Object) null));
  }

  /** Test equalObjects after adding multiple instances at once with a null */
  public void testAddTwoEqualObjectsAtOnceWithNull() {
    assertThrows(