assertEquals(size + 1, multimap().size());
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  public void testPutNullValue_unsupported() {
    assertThrows(NullPointerException.class, () -> multimap().put(k1(), null));

    expectUnchanged();
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
  public void testPutNullKey() {
    int size = getNumElements();

    List<Object> list = new ArrayList<>(equalityGroup.length);
    for (int i = 0; i < equalityGroup.length; i++) {
      Object element = equalityGroup[i];
      if (element == null) {
        throw new NullPointerException("at index " + i);
      }
      list.add(element);
    }
    equalityGroups.add(list);
    return this;
  }

  /** Run tests on equals method, throwing a failure on an invalid test */

    assertEquals(size + 1, multimap().size());
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  public void testPutNullValue_unsupported() {
    assertThrows(NullPointerException.class, () -> multimap().put(k1(), null));

    expectUnchanged();
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
  public void testPutNullKey() {
    int size = getNumElements();

  @Override
  public void setUp() {
    fakePool = new FakeExecutor();
    e = new SequentialExecutor(fakePool);
  }

  public void testConstructingWithNullExecutor_fails() {
    assertThrows(NullPointerException.class, () -> new SequentialExecutor(null));
  }

  public void testBasics() {
    final AtomicInteger totalCalls = new AtomicInteger();
    Runnable intCounter =
        new Runnable() {
          @Override

    testComparator(comparator, Integer.MIN_VALUE, -1, 0, 1, Integer.MAX_VALUE);
    assertThrows(NullPointerException.class, () -> comparator.compare(1, null));
    assertThrows(NullPointerException.class, () -> comparator.compare(null, 2));
    assertThrows(NullPointerException.class, () -> comparator.compare(null, null));
    assertSame(comparator, reserialize(comparator));

    testComparator(comparator, Integer.MIN_VALUE, -1, 0, 1, Integer.MAX_VALUE);
    assertThrows(NullPointerException.class, () -> comparator.compare(1, null));
    assertThrows(NullPointerException.class, () -> comparator.compare(null, 2));
    assertThrows(NullPointerException.class, () -> comparator.compare(null, null));
    assertSame(comparator, reserialize(comparator));

   * streams.
   *
   * <p>If the stream has nondeterministic order, this has equivalent semantics to {@link
   * Stream#findAny} (which you might as well use).
   *
   * @see Stream#findFirst()
   * @throws NullPointerException if the last element of the stream is null
   */
  /*
   * By declaring <T> instead of <T extends @Nullable Object>, we declare this method as requiring a

   *
   * @param collection a collection of {@code Number} instances
   * @return an array containing the same values as {@code collection}, in the same order, converted
   *     to primitives
   * @throws NullPointerException if {@code collection} or any of its elements is null
   * @since 1.0 (parameter was {@code Collection<Byte>} before 12.0)
   */
  public static byte[] toArray(Collection<? extends Number> collection) {

        }
      }
    }
  }

  public void testToArray_withNull() {
    List<@Nullable Double> list = Arrays.asList((double) 0, (double) 1, null);
    assertThrows(NullPointerException.class, () -> Doubles.toArray(list));
  }

  public void testToArray_withConversion() {
    double[] array = {(double) 0, (double) 1, (double) 2};

   *
   * @param collection a collection of {@code Character} objects
   * @return an array containing the same values as {@code collection}, in the same order, converted
   *     to primitives
   * @throws NullPointerException if {@code collection} or any of its elements is null
   */
  public static char[] toArray(Collection<Character> collection) {
    if (collection instanceof CharArrayAsList) {