I have many windows and mac system users in my office & and mac users use Xcode for development. I have a mac mini server with 16GB RAM, i want to use it as a xcode server, means is that possible some way that multiple window or mac user connect that mac mini server, work on xcode and logout when ever he wants. I also tried screen sharing for mac users and vnc for windows system but both ways are very slow to respond. I heard somewhere like Xcode server i searched for it but didn't get is properly. Can xcode server solve my problem? Please suggest any idea.
I'm not sure that Xcode Server provides that functionality. Xcode Server (part of macosx server) is a continuous integration solution, which means that your developers work on their own machines with their local tools and push code to a repo accessed by the Xcode server, which builds & tests the newly submitted code.
see Xcode Continuous Integration for a far better explanation of the workflow.
I don't know of any solution (other than vnc/screen sharing) that will allow you to share the Xcode app on the server between multiple users.