}

  /**
   * @return an array of the proper size with {@code null} as the key of the middle element.
   */
  protected Entry<K, V>[] createArrayWithNullKey() {
    Entry<K, V>[] array = createSamplesArray();
    int nullKeyLocation = getNullLocation();
    Entry<K, V> oldEntry = array[nullKeyLocation];
    array[nullKeyLocation] = Helpers.mapEntry(null, oldEntry.getValue());
    return array;
  }

  /**

    resetContainer();
  }

  /** @return an array of the proper size with {@code null} inserted into the middle element. */
  protected E[] createArrayWithNullElement() {
    E[] array = createSamplesArray();
    array[getNullLocation()] = null;
    return array;
  }

  protected void initCollectionWithNullElement() {
    E[] array = createArrayWithNullElement();

    }
  }

  /** @return an array of the proper size with {@code null} as the key of the middle element. */
  protected Entry<K, V>[] createArrayWithNullKey() {
    Entry<K, V>[] array = createSamplesArray();
    int nullKeyLocation = getNullLocation();
    Entry<K, V> oldEntry = array[nullKeyLocation];
    array[nullKeyLocation] = entry(null, oldEntry.getValue());
    return array;
  }

  protected V getValueForNullKey() {

    return new Enums();
  }

  @Override
  public Set<AnEnum> create(Object... elements) {
    AnEnum[] array = new AnEnum[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (AnEnum) e;
    }
    return create(array);
  }

  protected abstract Set<AnEnum> create(AnEnum[] elements);

  @Override
  public AnEnum[] createArray(int length) {

    return new Unhashables();
  }

  @Override
  public T create(Object... elements) {
    UnhashableObject[] array = createArray(elements.length);
    int i = 0;
    for (Object e : elements) {
      array[i++] = (UnhashableObject) e;
    }
    return create(array);
  }

  /**
   * Creates a new collection containing the given elements; implement this method instead of {@link
   * #create(Object...)}.

    return new Strings();
  }

  @Override
  public Set<String> create(Object... elements) {
    String[] array = new String[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (String) e;
    }
    return create(array);
  }

  protected abstract Set<String> create(String[] elements);

  @Override
  public String[] createArray(int length) {

    return new Ints();
  }

  @Override
  public Set<Integer> create(Object... elements) {
    Integer[] array = new Integer[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (Integer) e;
    }
    return create(array);
  }

  protected abstract Set<Integer> create(Integer[] elements);

  @Override
  public Integer[] createArray(int length) {

    @SuppressWarnings("unchecked")
    Entry<String, String>[] array = (Entry<String, String>[]) new Entry<?, ?>[entries.length];
    int i = 0;
    for (Object o : entries) {
      @SuppressWarnings("unchecked")
      Entry<String, String> e = (Entry<String, String>) o;
      array[i++] = e;
    }
    return create(array);
  }

  protected abstract BiMap<String, String> create(Entry<String, String>[] entries);

    @SuppressWarnings("unchecked") // Trying to test generic array
    ImmutableList<Integer>[] array =
        (ImmutableList<Integer>[]) new ImmutableList<?>[] {ImmutableList.of(1)};
    TypeToken<ImmutableList<Integer>[]> type = new TypeToken<ImmutableList<Integer>[]>() {};
    ImmutableTypeToInstanceMap<Iterable<?>[]> map =
        ImmutableTypeToInstanceMap.<Iterable<?>[]>builder().put(type, array).build();
    assertEquals(1, map.size());

    assertTrue("addAll(n, containsNull) should return true", getList().addAll(0, containsNull));
    /*
     * We need (E) to force interpretation of null as the single element of a
     * varargs array, not the array itself
     */
    expectAdded(0, (E) null);
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)