code: public static void assertNotSame(String message, Object unexpected,
              Object actual) {
          if (unexpected == actual) {
              failSame(message);
          }
      }
docs: Asserts that two objects do not refer to the same object. If they do
  refer to the same object, an {@link AssertionError} is thrown with the
  given message.
  
  @param message the identifying message for the {@link AssertionError} (<code>null</code>
  okay)
  @param unexpected the object you don't expect
  @param actual the object to compare to <code>unexpected</code>