@Override
    public void destroy() {
        // If the destroy method is being called, the Openfire instance is being shutdown.
        // Therefore, clear out the list of plugin filters.
        filters.clear();
    }
This class is a Filter implementation itself. It acts as a dynamic proxy to filters that are registered by
Openfire plugins.
xmppserver/src/main/java/org/jivesoftware/admin/PluginFilter.java