Listing users connected to the Studio and TAC could help customers that see an error message such as "The maximum number of licenses has been taken".
This applies to Talend version 5.3.1 and above.
You can use the Talend Administration Console (TAC) servlet ucache as in this url :
where tac_url = server_ip:tomcat_port/org.talend.administrator
This will provide you the details of all connected users in both TAC and Studios.
UsersCache: id=0, email@example.com, application=webapp, expiration=Thu Oct 17 20:17:55 CEST 2013 id=3, firstname.lastname@example.org, application=Studio, expiration=Thu Oct 17 20:17:18 CEST 2013 id=4, email@example.com, application=Studio, expiration=Thu Oct 17 20:17:41 CEST 2013
This enables administrators to check all connected users without querying the TAC Database.