* checkNotNull *should* be annotated to require it to be non-null.
   *
   * However, for a variety of reasons, Google developers have written a ton of code over the past
   * decade that assumes that they can use checkNotNull for non-precondition checks. I had hoped to
   * take a principled stand on this, but the amount of such code is simply overwhelming. To avoid

   *
   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
   * safe to do so. The exact circumstances under which a copy will or will not be performed are
   * undocumented and subject to change.
   *
   * @throws NullPointerException if any key or value in {@code map} is null
   * @throws IllegalArgumentException if any two keys are equal according to the comparator
   */

  /**
   * Test-helper method that performs {@code nThreads} concurrent calls to {@code cache.get(key)} or
   * {@code cache.getUnchecked(key)}, and returns a List containing each of the results. The result
   * for any given call to {@code cache.get} or {@code cache.getUnchecked} is the value returned, or
   * the exception thrown.
   *
   * <p>As we iterate from {@code 0} to {@code nThreads}, threads with an even index will call

  }

  private static <E> List<E> list(E... elements) {
    return ImmutableList.copyOf(elements);
  }

  /**
   * Utility method to verify that the given LinkedHashSet is equal to and hashes identically to a
   * set constructed with the elements in the given collection. Also verifies that the ordering in
   * the set is the same as the ordering of the given contents.
   */

    } catch (NullPointerException e) {
    }
    try {
      result.next();
      fail("no exception thrown");
    } catch (NullPointerException e) {
    }
    // There is no way to get "through" to the 3.  Buh-bye
  }

  public void testConcatVarArgsContainingNull() {
    try {
      Iterators.concat(iterateOver(1, 2), null, iterateOver(3), iterateOver(4), iterateOver(5));

   * is what most users want and expect it to do.
   *
   * <p>This behavior can't be broadly guaranteed, but has been tested with OpenJDK 1.7 and 1.8.
   *
   * @param expectedSize the number of elements you expect to add to the returned set
   * @return a new, empty hash set with enough capacity to hold {@code expectedSize} elements
   *     without resizing

   *
   * <p>The default implementation uses {@link #indexIn(CharSequence)} to find the first matching
   * character, then iterates the remainder of the sequence calling {@link #matches(char)} for each
   * character.
   *
   * @param sequence the character sequence to replace matching characters in
   * @param replacement the character to append to the result string in place of each matching
   *     character in {@code sequence}

        to.isSupertypeOf(from));
    assertTrue(
        to.getType() + " is expected to be a supertype of " + from.getType(),
        to.isSupertypeOf(from));
    assertTrue(
        from.getType() + " is expected to be a subtype of " + to.getType(), from.isSubtypeOf(to));
  }

  private static void assertNotAssignable(TypeToken<?> from, TypeToken<?> to) {
    assertFalse(

     * traverse. When nodes would otherwise be changed, new nodes are created to replace them. This
     * works well for hash tables since the bin lists tend to be short. (The average length is less
     * than two.)
     *
     * Read operations can thus proceed without locking, but rely on selected uses of volatiles to

  /**
   * Marks the given step final and waits for it to fail. Expects the failure exception to match
   * {@link AbstractClosingFutureTest#exception}.
   */
  abstract void assertFinallyFailsWithException(ClosingFuture<?> closingFuture);

  /** Waits for the given step to be canceled. */
  abstract void assertBecomesCanceled(ClosingFuture<?> closingFuture) throws ExecutionException;