code: public void setLanguageCookie(String language, RouteContext routeContext) {
          String lang = getLanguageOrDefault(language);
          if (lang.equals(language)) {
              Cookie cookie = generateLanguageCookie(language);
              routeContext.getResponse().cookie(cookie);
          } else {
              throw new PippoRuntimeException("'{}' is not a registered language!", language);
          }
      }
docs: Sets the application language cookie.
  <p>
  If the language does not match a registered language or language
  component an exception is thrown.
  </p>
  
  @param language
  @param routeContext
  @throws PippoRuntimeException