+ "justo commodo quam bibendum ut gravida leo accumsan. Nullam malesuada sagittis diam, "
          + "quis suscipit mauris euismod vulputate. Pellentesque ultrices tellus sed lorem "
          + "aliquet pulvinar. Nam lorem nunc, ultrices at auctor non, scelerisque eget turpis. "
          + "Nullam eget varius erat. Sed a lorem id arcu dictum euismod. Fusce lectus odio, "

          + "justo commodo quam bibendum ut gravida leo accumsan. Nullam malesuada sagittis diam, "
          + "quis suscipit mauris euismod vulputate. Pellentesque ultrices tellus sed lorem "
          + "aliquet pulvinar. Nam lorem nunc, ultrices at auctor non, scelerisque eget turpis. "
          + "Nullam eget varius erat. Sed a lorem id arcu dictum euismod. Fusce lectus odio, "

    assertTrue("add(null) should return true", collection.add(null));
    expectAdded((E) null);
  }

  @CollectionFeature.Require(value = SUPPORTS_ADD, absent = ALLOWS_NULL_VALUES)
  public void testAdd_nullUnsupported() {
    assertThrows(NullPointerException.class, () -> collection.add(null));
    expectUnchanged();
    expectNullMissingWhenNullUnsupported("Should not contain null after unsupported add(null)");
  }

    assertTrue("add(null) should return true", collection.add(null));
    expectAdded((E) null);
  }

  @CollectionFeature.Require(value = SUPPORTS_ADD, absent = ALLOWS_NULL_VALUES)
  public void testAdd_nullUnsupported() {
    assertThrows(NullPointerException.class, () -> collection.add(null));
    expectUnchanged();
    expectNullMissingWhenNullUnsupported("Should not contain null after unsupported add(null)");
  }

   * 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

  @Override
  public boolean contains(@CheckForNull Object target) {
    @Nullable Object[] table = this.table;
    if (target == null || table.length == 0) {
      return false;
    }
    for (int i = Hashing.smearedHash(target); ; i++) {
      i &= mask;
      Object candidate = table[i];
      if (candidate == null) {
        return false;
      } else if (candidate.equals(target)) {
        return true;
      }
    }
  }

      for (Object element : contents) {
        if (element == null) {
          throw new NullPointerException();
        }
      }
    }
  }

  @Override
  public int size() {
    return contents.length;
  }

  @Override
  public boolean contains(@Nullable Object object) {
    if (!allowNulls) {
      // behave badly
      if (object == null) {
        throw new NullPointerException();
      }
    }

    features.add(CollectionFeature.SUBSET_VIEW);
    if (features.remove(CollectionFeature.ALLOWS_NULL_VALUES)) {
      // the null value might be out of bounds, so we can't always construct a subset with nulls
      features.add(CollectionFeature.ALLOWS_NULL_QUERIES);
      // but add null might still be supported if it happens to be within range of the subset
      suppressing.add(CollectionAddTester.getAddNullUnsupportedMethod());

    features.add(CollectionFeature.SUBSET_VIEW);
    if (features.remove(CollectionFeature.ALLOWS_NULL_VALUES)) {
      // the null value might be out of bounds, so we can't always construct a subset with nulls
      features.add(CollectionFeature.ALLOWS_NULL_QUERIES);
      // but add null might still be supported if it happens to be within range of the subset
      suppressing.add(CollectionAddTester.getAddNullUnsupportedMethod());

  /**
   * Visits the given types. Null types are ignored. This allows subclasses to call {@code
   * visit(parameterizedType.getOwnerType())} safely without having to check nulls.
   */
  public final void visit(@Nullable Type... types) {
    for (Type type : types) {
      if (type == null || !visited.add(type)) {
        // null owner type, or already visited;
        continue;
      }