code: public String format(final String code, @Nullable final Object... args) {
      String pattern = getMessage(code);
      if (args != null) {
        return String.format(pattern, args);
      }
      else {
        return pattern;
      }
    }
docs: Format a message (based on {@link MessageFormat} using the message
  from the resource bundles using the given code as a pattern and the
  given objects as arguments.