code: public void shutdown(Long id) {
  
          Watchdog wd = (Watchdog) this.registeredWachdogs.get(id);
          if (wd == null) {
              throw new IllegalStateException("Watchdog " + id + " ist not registered");
          }
          wd.kill();
          this.deregisterWatchdog(id);
      }
docs: stops the the Watchdog with the given id
  The executing thread of the watchdog is stopped and the watchdog is removed from the registry.
  It can nor be restarted
  
  @throws IllegalStateException Watchdog does not exist,
  check existence with {@link #findWatchdog(Long)}
  @see #restart(Long)
  @see #stop(Long)