* Ordering.natural()} if the elements are ordered by their natural ordering.
   */
  Comparator<? super T> comparator();

  /**
   * Returns an iterator over elements of type {@code T}. The elements are returned in nondecreasing
   * order according to the associated {@link #comparator}.
   */
  @Override
  Iterator<T> iterator();

   * Ordering.natural()} if the elements are ordered by their natural ordering.
   */
  Comparator<? super T> comparator();

  /**
   * Returns an iterator over elements of type {@code T}. The elements are returned in nondecreasing
   * order according to the associated {@link #comparator}.
   */
  @Override
  Iterator<T> iterator();

  }

  /**
   * Returns an immutable multimap containing the specified entries. The returned multimap iterates
   * over keys in the order they were first encountered in the input, and the values for each key
   * are iterated in the order they were encountered. If two values for the same key are {@linkplain
   * Object#equals equal}, the first value encountered is used.
   *

    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      StringBuilder sb = new StringBuilder();
      Iterator<String> iterator = components.iterator();
      if (iterator.hasNext()) {
        sb.append(iterator.next().toString());
        while (iterator.hasNext()) {
          sb.append(DELIMITER_STRING);
          sb.append(iterator.next());
        }
      }
      dummy ^= sb.toString().length();
    }
    return dummy;
  }

   * the given line separator.
   *
   * @throws IOException if an I/O error occurs while writing to this sink
   */
  public void writeLines(Iterable<? extends CharSequence> lines, String lineSeparator)
      throws IOException {
    writeLines(lines.iterator(), lineSeparator);
  }

  /**
   * Writes the given lines of text to this sink with each line (including the last) terminated with

    return new Iterable<String>() {
      @Override
      public Iterator<String> iterator() {
        return splittingIterator(sequence);
      }

      @Override
      public String toString() {
        return Joiner.on(", ")
            .appendTo(new StringBuilder().append('['), this)
            .append(']')
            .toString();
      }
    };
  }

    Iterator<String> iterator = asList("a", "b", "a").iterator();
    List<String> list = ImmutableList.copyOf(iterator);
    assertEquals(asList("a", "b", "a"), list);
  }

  public void testCopyOf_iteratorContainingNull() {
    Iterator<@Nullable String> iterator =
        Arrays.<@Nullable String>asList("a", null, "b").iterator();
    assertThrows(

  }

  @Override
  Iterator<Entry<E>> entryIterator() {
    // AbstractIterator makes this fairly clean, but it doesn't support remove(). To support
    // remove(), we create an AbstractIterator, and then use ForwardingIterator to delegate to it.
    Iterator<Entry<E>> readOnlyIterator =
        new AbstractIterator<Entry<E>>() {
          private final Iterator<Map.Entry<E, AtomicInteger>> mapEntries =

      Comparator<? super E> comparator, Iterator<? extends E> elements) {
    return new Builder<E>(comparator).addAll(elements).build();
  }

  /**
   * Returns an immutable sorted set containing the given elements sorted by the given {@code
   * Comparator}. When multiple elements are equivalent according to {@code compare()}, only the
   * first one specified is included. This method iterates over {@code elements} at most once.
   *

  }

  /**
   * A sensible default implementation of {@link #iterator}, in terms of {@link #listIterator()}. If
   * you override {@link #listIterator()}, you may wish to override {@link #iterator} to forward to
   * this implementation.
   *
   * @since 7.0
   */
  protected Iterator<E> standardIterator() {
    return listIterator();
  }

  /**