Loading Monitors
From Documentation
This article is out of date, please refer to https://docs.zkoss.org/zk_dev_ref/ for more up to date information.
To know the loading of an application, you could implement Monitor to count the number of desktops, sessions and requests.
Once implemented, you could register it by specifying the following in WEB-INF/zk.xml (assume the class is called foo.MyStatistic):
<zk>
<listener>
<listener-class>foo.MyStatistic</listener-class>
</listener>
</zk>