public abstract boolean equals(@CheckForNull Object object);

  /**
   * Returns a hash code for this instance.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this class leaves the specific choice of
   * hash code unspecified, unlike the Java 8+ equivalent.
   */
  @Override
  public abstract int hashCode();

  /**
   * Returns a string representation for this instance.
   *

  public abstract boolean equals(@CheckForNull Object object);

  /**
   * Returns a hash code for this instance.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this class leaves the specific choice of
   * hash code unspecified, unlike the Java 8+ equivalent.
   */
  @Override
  public abstract int hashCode();

  /**
   * Returns a string representation for this instance.
   *

   *
   * @deprecated If you must interoperate with a system that requires MD5, then use this method,
   *     despite its deprecation. But if you can choose your hash function, avoid MD5, which is
   *     neither fast nor secure. As of January 2017, we suggest:
   *     <ul>
   *       <li>For security:
   *           {@link Hashing#sha256} or a higher-level API.

     *
     * <ul>
     *   <li>For an empty list, it is 1 (base case).
     *   <li>When r numbers are added to a list of n-r elements, the number of permutations is
     *       increased by a factor of (n choose r).
     * </ul>
     */
    private static <E> int calculateSize(
        List<E> sortedInputList, Comparator<? super E> comparator) {
      int permutations = 1;
      int n = 1;
      int r = 1;

   * #newArrayListWithCapacity} (see that method for further advice on usage).
   *
   * <p><b>Note:</b> This method will soon be deprecated. Even in the rare case that you do want
   * some amount of padding, it's best if you choose your desired amount explicitly.
   *
   * @param estimatedSize an estimate of the eventual {@link List#size()} of the new list
   * @return a new, empty {@code ArrayList}, sized appropriately to hold the estimated number of

     *
     * <ul>
     *   <li>For an empty list, it is 1 (base case).
     *   <li>When r numbers are added to a list of n-r elements, the number of permutations is
     *       increased by a factor of (n choose r).
     * </ul>
     */
    private static <E> int calculateSize(
        List<E> sortedInputList, Comparator<? super E> comparator) {
      int permutations = 1;
      int n = 1;
      int r = 1;

   * This is useful if the given service uses daemon threads, and we want to keep the JVM from
   * exiting immediately on shutdown, instead giving these daemon threads a chance to terminate
   * normally.
   *
   * @param service ExecutorService which uses daemon threads
   * @param terminationTimeout how long to wait for the executor to finish before terminating the
   *     JVM

 *         .onResultOf(getBarFunction)
 *         .nullsLast();
 * }</pre>
 *
 * Note that each chaining method returns a new ordering instance which is backed by the previous
 * instance, but has the chance to act on values <i>before</i> handing off to that backing instance.
 * As a result, it usually helps to read chained ordering expressions <i>backwards</i>. For example,
 * when {@code compare} is called on the above ordering:
 *

       * run the supermethod as usual.
       *
       * TODO: b/292578973: Use @AndroidIncompatible if we change our system to keep the methods in
       * place but to have the test runner skip them. However, note that if we choose to *both*
       * strip the methods *and* have the test runner not run them (for some unusual cases in which
       * we don't run the stripping test for technical reasons), then we'd be back to the problem

       * run the supermethod as usual.
       *
       * TODO: b/292578973: Use @AndroidIncompatible if we change our system to keep the methods in
       * place but to have the test runner skip them. However, note that if we choose to *both*
       * strip the methods *and* have the test runner not run them (for some unusual cases in which
       * we don't run the stripping test for technical reasons), then we'd be back to the problem