*
   * <p><b>Comparison to {@code java.util.Optional}:</b> this method is equivalent to Java 8's
   * {@code Optional.ofNullable}.
   */
  public static <T> Optional<T> fromNullable(@CheckForNull T nullableReference) {
    return (nullableReference == null) ? Optional.<T>absent() : new Present<T>(nullableReference);
  }

  /**
   * Returns the equivalent {@code com.google.common.base.Optional} value to the given {@code

  }

  protected void initMapWithNullKey() {
    resetMap(createArrayWithNullKey());
  }

  protected void initMapWithNullValue() {
    resetMap(createArrayWithNullValue());
  }

  /**
   * Equivalent to {@link #expectMissingKeys(Object[]) expectMissingKeys} {@code (null)} except that
   * the call to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *

  }

  /**
   * Returns an immutable sorted set containing the given elements sorted by their natural ordering.
   * When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
   * one specified is included.
   *
   * @throws NullPointerException if any element is null
   */

   * implicit).
   */
  protected Ordering() {}

  // Instance-based factories (and any static equivalents)

  /**
   * Returns the reverse of this ordering; the {@code Ordering} equivalent to {@link
   * Collections#reverseOrder(Comparator)}.
   *
   * <p><b>Java 8+ users:</b> Use {@code thisComparator.reversed()} instead.
   */

     *
     * @return The global settings file or {@code null} if none.
     */
    File getGlobalSettingsFile();

    /**
     * Sets the global settings file. A non-existent settings file is equivalent to empty settings. If both user
     * settings and global settings are given, the user settings take precedence.
     *
     * @param globalSettingsFile The global settings file, may be {@code null} to disable global settings.

   * stream is empty.
   *
   * <p>Equivalent to {@code stream.reduce((a, b) -> b)}, but may perform significantly better. This
   * method's runtime will be between O(log n) and O(n), performing better on <a
   * href="http://gee.cs.oswego.edu/dl/html/StreamParallelGuidance.html">efficiently splittable</a>
   * streams.
   *
   * <p>If the stream has nondeterministic order, this has equivalent semantics to {@link

   * implicit).
   */
  protected Ordering() {}

  // Instance-based factories (and any static equivalents)

  /**
   * Returns the reverse of this ordering; the {@code Ordering} equivalent to {@link
   * Collections#reverseOrder(Comparator)}.
   *
   * <p><b>Java 8+ users:</b> Use {@code thisComparator.reversed()} instead.
   */

   * that of {@code ((Integer) a).compareTo(b)}.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated; use the
   * equivalent {@link Integer#compare} method instead.
   *
   * @param a the first {@code int} to compare
   * @param b the second {@code int} to compare

    }
  }

  /**
   * Writes the given lines of text to this sink with each line (including the last) terminated with
   * the operating system's default line separator. This method is equivalent to {@code
   * writeLines(lines, System.getProperty("line.separator"))}.
   *
   * @throws IOException if an I/O error occurs while writing to this sink
   */

  }

  /**
   * Returns an immutable sorted set containing the given elements sorted by their natural ordering.
   * When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
   * one specified is included.
   *
   * @throws NullPointerException if any element is null
   */