* href="https://bugs.openjdk.org/browse/JDK-6409434">JDK-6409434</a> is fixed. It's unclear
   * whether nulls were to be permitted or forbidden, but presumably the eventual fix will be to
   * permit them, as it seems more likely that code would depend on that behavior than on the other.
   * Thus, we say the bug is in set(), which fails to support null.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection

  }

  /*
   * All the ContiguousSet generators below manually reject nulls here. In principle, we'd like to
   * defer that to Range, since it's ContiguousSet.create() that's used to create the sets. However,
   * that gets messy here, and we already have null tests for Range.
   */

  /*
   * These generators also rely on consecutive integer inputs (not necessarily in order, but no

   *
   * @param reference any array of the desired type
   * @param length the length of the new array
   */
  /*
   * The new array contains nulls, even if the old array did not. If we wanted to be accurate, we
   * would declare a return type of `@Nullable T[]`. However, we've decided not to think too hard

   *
   * @param reference any array of the desired type
   * @param length the length of the new array
   */
  /*
   * The new array contains nulls, even if the old array did not. If we wanted to be accurate, we
   * would declare a return type of `@Nullable T[]`. However, we've decided not to think too hard

   */
  /*
   * By declaring <T> instead of <T extends @Nullable Object>, we declare this method as requiring a
   * stream whose elements are non-null. However, the method goes out of its way to still handle
   * nulls in the stream. This means that the method can safely be used with a stream that contains
   * nulls as long as the *last* element is *not* null.
   *

      List<?> normalValues = (List<?>) asList(elements);
      List<E> extremeValues = new ArrayList<>();

      // nulls are usually out of bounds for a subset, so ban them altogether
      for (Object o : elements) {
        if (o == null) {
          throw new NullPointerException();
        }
      }

      // prepare extreme values to be filtered out of view

    initThreeCopies();
    assertSetCountDecreasingFailure(e0(), 1);
  }

  // setCount with nulls:

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  public void testSetCount_removeNull_nullSupported() {
    initCollectionWithNullElement();
    assertSetCount(null, 0);
  }

  @CollectionFeature.Require(
      value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES},

      newDelegate.add(element(i));
    }
    this.table = newDelegate;
    this.entries = null;
    this.elements = null;
    incrementModCount();
    return newDelegate;
  }

  @VisibleForTesting
  boolean isUsingHashFloodingResistance() {
    return delegateOrNull() != null;
  }

  /** Stores the hash table mask as the number of bits needed to represent an index. */

   *             impossible.
   *         <li>Test will fail if the constructor or factory method throws exception.
   *       </ul>
   *   <li>If there is no non-private constructor or non-private static factory method declared by
   *       {@code cls}, instance methods are skipped for nulls test.

   * removal operations, and these are reflected in the underlying table.
   *
   * <p>It's acceptable for the underlying table to contain null keys, and even null values provided
   * that the function is capable of accepting null input. The transformed table might contain null
   * values, if the function sometimes gives a null result.
   *
   * <p>The returned table is not thread-safe or serializable, even if the underlying table is.
   *