code: @Override
      protected MessageFormat resolveCode(String code, Locale locale) {
          MessageFormat messageFormat = null;
          for (int i = 0; messageFormat == null && i < this.basenames.length; i++) {
              ResourceBundle bundle = getResourceBundle(this.basenames[i], locale);
              if (bundle != null) {
                  messageFormat = getMessageFormat(bundle, code, locale);
              }
          }
          return messageFormat;
      }
docs: Resolves the given message code as key in the registered resource bundles,
  using a cached MessageFormat instance per message code.