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 */

        assertTrue(exception.getStackTrace().length > 0);

        // Should contain this test method in stack trace
        boolean foundTestMethod = false;
        for (StackTraceElement element : exception.getStackTrace()) {
            if (element.getMethodName().contains("testStackTracePreservation")) {
                foundTestMethod = true;
                break;
            }
        }
        assertTrue(foundTestMethod);

  }

  private SafeTreeSet(NavigableSet<E> delegate) {
    this.delegate = delegate;
    for (E e : this) {
      checkValid(e);
    }
  }

  @Override
  public boolean add(E element) {
    return delegate.add(checkValid(element));
  }

  @Override
  public boolean addAll(Collection<? extends E> collection) {
    for (E e : collection) {
      checkValid(e);
    }
    return delegate.addAll(collection);
  }

    return new Strings();
  }

  @Override
  public Collection<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 Collection<String> create(String[] elements);

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

    return new Strings();
  }

  @Override
  public Queue<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 Queue<String> create(String[] elements);

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

    this.equivalence = checkNotNull(equivalence);
  }

  /**
   * Different orderings for combining the elements of an input array, which must all produce the
   * same result.
   */
  enum CollectStrategy {
    /** Get one accumulator and accumulate the elements into it sequentially. */
    SEQUENTIAL {
      @Override

		},
		// With a list of only one element nothing to sort.
		{
			ipList:       []string{"hostname"},
			sortedIPList: []string{"hostname"},
		},
		// With a list of only one element nothing to sort.
		{
			ipList:       []string{"127.0.0.1"},
			sortedIPList: []string{"127.0.0.1"},
		},
		// Non parsable ip is assumed to be hostame and gets preserved
		// as the left most elements, regardless of IP based sorting.
		{

    return new Chars();
  }

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

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

    return new Colliders();
  }

  @Override
  public Object[] createArray(int length) {
    return new Object[length];
  }

  /** Returns the original element list, unchanged. */
  @Override
  public List<Object> order(List<Object> insertionOrder) {
    return insertionOrder;
  }