code: public void warnv(String format, Object param1, Object param2, Object param3) {
          if (isEnabled(Level.WARN)) {
              doLog(Level.WARN, FQCN, format, new Object[] { param1, param2, param3 }, null);
          }
      }
docs: Issue a log message with a level of WARN using {@link java.text.MessageFormat}-style formatting.
  
  @param format the message format string
  @param param1 the first parameter
  @param param2 the second parameter
  @param param3 the third parameter