code: public static Exception stopQuietly(Service service) {
      try {
        stop(service);
      } catch (Exception e) {
        LOG.warn("When stopping the service " + service.getName()
                     + " : " + e,
                 e);
        return e;
      }
      return null;
    }
docs: Stop a service; if it is null do nothing. Exceptions are caught and
  logged at warn level. (but not Throwables). This operation is intended to
  be used in cleanup operations
  
  @param service a service; may be null
  @return any exception that was caught; null if none was.