load balancing in java servelrt servers

I need to create a project in java using jsp,servlet,html and load balancing. I have created basic file retrieval system in which several users create their files( In doc or txt format) and they can edit also the files. Each file is stored in a server system. In that i have created a sign up form in which new user registers themselves. and after that they can create files using text editor. Registered users can edit or delete files. Now i have to implement load balancing in this. When several users login with their credentials,there should be a load balancer which directs the request to one of the availaible machines which connect with database and retrieve the result and send it back to load balancer which send it back to client.