Hosting for java simulation

Hello,

I need a web server that i can run a java simulation on. The simulation is for a social experiment. Users would login and use the site the same way as  other online games. The only problem is i need to be able to program the server and how the server responds to the clients. I cant use many of the pre built tools for making websites. Are there any hosting companies that offer this? I don't have a lot of money to spend on this project. Any help would be really appreciated.