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) {

   * 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

   * 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

    assertFailure(
        Runnable.class,
        runnable ->
            () -> {
              runnable.run();
              runnable.run();
            },
        "run()",
        "invoked more than once");
  }

  public void testFailsToForwardParameters() {
    assertFailure(Adder.class, FailsToForwardParameters::new, "add(", "Parameter #0");
  }

  public void testForwardsToTheWrongMethod() {

    assertFailure(
        Runnable.class,
        runnable ->
            () -> {
              runnable.run();
              runnable.run();
            },
        "run()",
        "invoked more than once");
  }

  public void testFailsToForwardParameters() {
    assertFailure(Adder.class, FailsToForwardParameters::new, "add(", "Parameter #0");
  }

  public void testForwardsToTheWrongMethod() {

        }
      }
    }
  }

  /**
   * Sets the default value for {@code type}, when dummy value for a parameter of the same type
   * needs to be created in order to invoke a method or constructor. The default value isn't used in
   * testing {@link Object#equals} because more than one sample instances are needed for testing
   * inequality.
   */

   * values, if the function sometimes gives a null result.
   *
   * <p>The returned map is not thread-safe or serializable, even if the underlying map is.
   *
   * <p>The function is applied lazily, invoked when needed. This is necessary for the returned map
   * to be a view, but it means that the function will be applied many times for bulk operations

   * values, if the function sometimes gives a null result.
   *
   * <p>The returned map is not thread-safe or serializable, even if the underlying map is.
   *
   * <p>The function is applied lazily, invoked when needed. This is necessary for the returned map
   * to be a view, but it means that the function will be applied many times for bulk operations

        }
      }
    }
  }

  /**
   * Sets the default value for {@code type}, when dummy value for a parameter of the same type
   * needs to be created in order to invoke a method or constructor. The default value isn't used in
   * testing {@link Object#equals} because more than one sample instances are needed for testing
   * inequality.
   */

 * differences include:
 *
 * <ul>
 *   <li>A stream is <i>single-use</i>; it becomes invalid as soon as any "terminal operation" such
 *       as {@code findFirst()} or {@code iterator()} is invoked. (Even though {@code Stream}
 *       contains all the right method <i>signatures</i> to implement {@link Iterable}, it does not
 *       actually do so, to avoid implying repeat-iterability.) {@code FluentIterable}, on the other