code: public Locale getLocaleOrDefault(RouteContext routeContext) {
          String language = getLanguageOrDefault(routeContext);
          return Locale.forLanguageTag(language);
      }
docs: Returns the Java Locale for the Request & Response cycle. If the language
  specified in the Request/Response cycle can not be mapped to a Java
  Locale, the default language Locale is returned.
  
  @param routeContext
  @return a Java Locale