code: public String getFormatStringWithoutDefaulting(Locale locale, String key) {
          for (String s : toStrings(locale)) {
              String msg = get(s).getProperty(key);
              if(msg!=null && msg.length()>0)
                  return msg;
          }
          return null;
      }
docs: Works like {@link #getFormatString(Locale, String)} except there's no
  searching up the delegation chain.