active sessions

[vtr]

Hi all,   Can any one suggest some method to find out how many users are at present logged in my site. The problem is when the number exeeds a particular limit the tomcat crashes with an error message indicating that the jdbc connections has exeeded some limit.  I want to track the no of users when the server crash happens. any suggestion to avoid this situation is also welcome   thanx in advance.     Ravi kumar.