* protected to allow subclasses to override the fastpath escaping function to inline their
   * escaping test. See {@link CharEscaperBuilder} for an example usage.
   *
   * <p>This method is not reentrant and may only be invoked by the top level {@link
   * #escape(String)} method.
   *
   * @param s the literal string to be escaped
   * @param index the index to start escaping from
   * @return the escaped form of {@code string}

   * protected to allow subclasses to override the fastpath escaping function to inline their
   * escaping test. See {@link CharEscaperBuilder} for an example usage.
   *
   * <p>This method is not reentrant and may only be invoked by the top level {@link
   * #escape(String)} method.
   *
   * @param s the literal string to be escaped
   * @param index the index to start escaping from
   * @return the escaped form of {@code string}

   * href="http://en.wikipedia.org/wiki/Memoization">memoization</a>
   *
   * <p>The returned supplier is thread-safe. The delegate's {@code get()} method will be invoked at
   * most once unless the underlying {@code get()} throws an exception. The supplier's serialized
   * form does not contain the cached value, which will be recalculated when {@code get()} is called

    return MoreObjects.firstNonNull(valueStrength, Strength.STRONG);
  }

  /**
   * Builds a thread-safe map. This method does not alter the state of this {@code MapMaker}
   * instance, so it can be invoked again to create multiple independent maps.
   *
   * <p>The bulk operations {@code putAll}, {@code equals}, and {@code clear} are not guaranteed to

   *
   * <p>{@code addListener} guarantees execution ordering across calls to a given listener but not
   * across calls to multiple listeners. Specifically, a given listener will have its callbacks
   * invoked in the same order as the underlying service enters those states. Additionally, at most
   * one of the listener's callbacks will execute at once. However, multiple listeners' callbacks

    T instance = invoke(factory, args);
    if (instance == null) {
      throw new FactoryMethodReturnsNullException(factory);
    }
    return instance;
  }

  private static <T> @Nullable T invoke(Invokable<?, ? extends T> factory, List<?> args)
      throws InvocationTargetException, IllegalAccessException {
    T returnValue = factory.invoke(null, args.toArray());
    if (returnValue == null) {

   * is true.
   *
   * <p>For example:
   *
   * {@snippet :
   * Equivalence<Person> SAME_AGE = Equivalence.equals().onResultOf(GET_PERSON_AGE);
   * }
   *
   * <p>{@code function} will never be invoked with a null value.
   *
   * <p>Note that {@code function} must be consistent according to {@code this} equivalence
   * relation. That is, invoking {@link Function#apply} multiple times for a given value must return

 * parameter whose declaration or type isn't annotated with an annotation with the simple name
 * {@code Nullable}, {@code CheckForNull}, {@code NullableType}, or {@code NullableDecl}.
 *
 * <p>The tested methods and constructors are invoked -- each time with one parameter being null and
 * the rest not null -- and the test fails if no expected exception is thrown. {@code
 * NullPointerTester} uses best effort to pick non-null default values for many common JDK and Guava

 * methods will throw {@link NullPointerException} if any given element is null.
 *
 * <p><b>Warning: joiner instances are always immutable</b>; a configuration method such as {@code
 * useForNull} has no effect on the instance it is invoked on! You must store and use the new joiner
 * instance returned by the method. This makes joiners thread-safe, and safe to store as {@code
 * static final} constants.
 *
 * {@snippet :
 * // Bad! Do not do this!

   * and {@code get()} will return a general {@code Collection} as opposed to a {@code List} or a
   * {@code Set}.
   *
   * <p>The function is applied lazily, invoked when needed. This is necessary for the returned
   * multimap to be a view, but it means that the function will be applied many times for bulk