code: public void restart(RuntimeException cause) {
          if (isProdMode()) throw cause;
          if (!(cause instanceof ClassReloadException)) {
              String msg = cause.getMessage();
              if (cause instanceof RythmException) {
                  RythmException re = (RythmException) cause;
                  msg = re.getSimpleMessage();
              }
              logger.warn("restarting rythm engine due to %s", msg);
          }
          restart();
      }
docs: Restart the engine with an exception as the cause.
  <p><b>Note</b>, this is not supposed to be called by user application</p>
  
  @param cause