there is no view to get informations about current connected user.
I know that Web applications with login administrate that by themselve, or redirect to a service-page if there is an apache in front of.
For other issues you havn't such option.
The JBoss shutdown is mostly graceful and let running request finish, but this is no guarantee because most application have a sequence of different calls to the server and this can not detected.
Admin task you can do with jmx- web- or admin-console depend on the JBoss version. See the start page http://<host>:8080 of the server for links.