Is there any way to expire web application using java?

I am developing one web application, in that application users can login and use the respective features.But the problem is,we provide the server to them with all source files.And the users can use that application internally by typing the server system IP address.What I need is, I need to make that application active only for particular time period, once it reached the particular date, it want to display like it is expired.

How can I achieve that and the main problem is we provide the server to them,that is what am struggling?? So please anyone guide me ,how can I achieve that.