1. View users online/offline status coderanch.com
2. help needed for java to calculate number of user online coderanch.com
The approach will depend on what you mean by active user. If you roll your own login, this is pretty easy to do. I have a demo application on my site that does exactly what you're trying to do. http://simple.souther.us/not-so-simple.html Look for SessionMonitor. Again, if you're just starting out with programming, Java, Servlets and/or JSP, this project might be a little ...
3. listing all online users on a JSP page coderanch.com