expectAdded(0, (E) null);
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)
  public void testAddAtIndex_nullUnsupported() {
    assertThrows(NullPointerException.class, () -> getList().add(0, null));
    expectUnchanged();
    expectNullMissingWhenNullUnsupported("Should not contain null after unsupported add(n, null)");
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)

            OtherPipeHandle result = target.unwrap(OtherPipeHandle.class);
        });

        // Null input: document current behavior (NPE from isAssignableFrom)
        assertThrows(NullPointerException.class, () -> target.unwrap(null));
    }

    @Test
    @DisplayName("getPipe, getPipeType, getUncPath delegate to underlying pipe")
    void testBasicAccessors() {

        new WrappedHashMapGenerator() {
          @Override
          Map<String, String> wrap(HashMap<String, String> map) {
            if (map.containsKey(null)) {
              throw new NullPointerException();
            }
            return new AbstractMap<String, String>() {
              @Override
              public Set<Entry<String, String>> entrySet() {
                return map.entrySet();

  public void testContainsNullValueNo() {
    assertFalse(multimap().containsValue(null));
  }

  @MapFeature.Require(absent = ALLOWS_NULL_VALUE_QUERIES)
  public void testContainsNullValueFails() {
    assertThrows(NullPointerException.class, () -> multimap().containsValue(null));
  }

     */
    @Override
    public int count(@Nullable Object element) {
      try {
        return unbox(countMap.get(element));
      } catch (NullPointerException | ClassCastException e) {
        return 0;
      }
    }

    /**
     * {@inheritDoc}
     *
     * <p>If the data in the multiset is modified by any other threads during this method, it is

     *
     * <p>Note that each builder class covariantly returns its own type from this method.
     *
     * @param element the element to add
     * @return this {@code Builder} instance
     * @throws NullPointerException if {@code element} is null
     */
    @CanIgnoreReturnValue
    public abstract Builder<E> add(E element);

    /**

  }

  @MapFeature.Require(absent = ALLOWS_NULL_KEY_QUERIES)
  public void testGet_nullNotContainedAndUnsupported() {
    try {
      assertNull("get(null) should return null or throw", get(null));
    } catch (NullPointerException tolerated) {
    }
  }

  @MapFeature.Require(ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testGet_nonNullWhenNullContained() {
    initMapWithNullKey();

  public void testFind_nullNotContainedAndUnsupported() {
    try {
      assertEquals(getMethodName() + "(nullNotPresent) should return -1 or throw", -1, find(null));
    } catch (NullPointerException tolerated) {
    }
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testFind_nonNullWhenNullContained() {
    initCollectionWithNullElement();

   * @throws NullPointerException if both {@code first} and {@code second} are null
   * @since 18.0 (since 3.0 as {@code Objects.firstNonNull}).
   */
  public static <T> T firstNonNull(@Nullable T first, @Nullable T second) {
    if (first != null) {
      return first;
    }
    if (second != null) {
      return second;
    }
    throw new NullPointerException("Both parameters are null");
  }

  /**

    @DisplayName("Reading with null array throws NullPointerException")
    void readNullArrayThrowsException() {
        // Create stream with valid message header and data
        byte[] data = new byte[] { 1 };
        InputStream in = new ByteArrayInputStream(concat(messageHeader(1), data));
        SocketInputStream sis = new SocketInputStream(in);

        // Should throw NullPointerException when reading with null array