Server with different instances

I have one application developed in Spring Framework and this application deals with large amount of data.So it would be better if I will give a dedicated application or separate instance to each customer.

I want to give them a separate URL for their organisation e.g. If company abc is there, then may be I can give them something like http://www.abc.appname.com...and it will like dedicated to that client.

How can I do it? What are the different ways to achieve it so that each client can have its own server load etc.