@Override
    public void destroy() {
        Log.debug( "Destroying service with name '{}'.", serviceName );
        XMPPServer.getInstance().getEntityCapabilitiesManager().removeListener(this);

        super.destroy();
        if (persistenceProviderManager!= null) {
            persistenceProviderManager.shutdown();
        }
    }
Manager of entities that interact with persistent storage of data (eg: the database).
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/PubSubModule.java