code: public String get(String key, RouteContext routeContext, Object... args) {
          String language = languages.getLanguageOrDefault(routeContext);
          return get(key, language, args);
      }
docs: Gets the requested localized message.
  <p/>
  <p>
  The current Request and Response are used to help determine the messages
  resource to use.
  <ol>
  <li>Exact locale match, return the registered locale message
  <li>Language match, but not a locale match, return the registered
  language message
  <li>Return the default resource message
  </ol>
  <p>
  The message can be formatted with optional arguments using the
  {@link java.text.MessageFormat} syntax.
  </p>
  <p>
  If the key does not exist in the messages resource, then the key name is
  returned.
  </p>
  
  @param key
  @param routeContext
  @param args
  @return the message or the key if the key does not exist