Java EE (Java Enterprise Edition) General Discussion

Hi,
can some one tell me the effective way to restrict the number of users(Logins) trying to Login to a web application developed in struts frame work and running on Tomcat server.
I exactly wanted is to restrict the number of users accessing my application, I have to make it to be accessed by limited number of users(Logins). I want to display a default page to the new user who are trying to login, if the limit is exceeded.

Thanks in advance.
Venkat.