Eclipse is an
IDE. If you are wishing to find the userid of a webapp user in a JSF webapp, Eclipse has nothing to do with it. Eclipse will not be running in the production server and therefore will not be able to help.
Any
J2EE webapp that wishes to know the webapp user's ID can obtain it from the HttpServletRequest using the getRemoteUser() method.
Providing that the webapp in question is using J2EE standard security and not some "clever" person's do-it-yourself login system.
It can be a little hard to obtain the actual HttpServletRequest object in JSF, since JSF is supposed to be platform independent and thus theoretically able to run in non-web environments. However, it's not that hard and what I personally do is provide a :"JSFUtils" service class where I put this kind of code so that I don't have to splatter platform-specific code all over my JSF webapp. If I want the userID, I just invoke my JSFUtils.getUserId() method.
For details on how to obtain the HttpServletRequest object in a JSF web application, ask in the JSF forum.
One other note: The webapp login user id is often
not the same as the LAN userID. If I was to connect to your webapp from my Linux desktop, I would not have a Windows LAN user ID at all on your LAN, but I would expect to have a webapp user ID to log into.