@Override
  public synchronized void stop() throws NoSuchObjectException {
    if (isRunning()) {
      isRunning = !UnicastRemoteObject.unexportObject(registry, true);
    }
  }
Stops this MBean: rmiregistry cannot accept anymore incoming calls

@see #start
geode-core/src/main/java/org/apache/geode/admin/jmx/internal/RMIRegistryService.java