Sometimes you may need to take the Alfresco-server down on short notice. It is nice to know which users are logged on the system that may possibly be performing some important work.
The information is not available through the Alfresco Administration interface. But there is another way. Connect to alfresco with a JMX client. JConsole can be used. Navigate to the bean “Alfresco->RepoServerMgmt->Operations”. There you will find a function called listUserNamesNonExpired(). That function will list all the currently logged in users.