restrict « User « JSP-Servlet Q&A

1. How to restrict two user with same username and password

To avoid locking people out forever, clear the table at server startup and make it so nobody is logged on. We have something very similar in a current system. If you have only one instance of your server - no load balanced machines or such things - you might as well manage all of this in memory.

4. Restrict opening same application more than once by a user

I have a web application. That need to be opened by a user only once. Opening of second instance should be restricted if it is from a different machine, or same machine different window or same window different tab. There is no login screen. Single sign on will be used while launching the app. I can able to achieve the first ...