Swing Application as server to host web services

Question

I have swing application. Basically I have used "floreant pos" and have customized based on my requirement. Now I want to the same operation what I do from my swing application but in the form of Rest web service.

1. When I start my swing application, there must be web services available to access from mobile app.
2. I need to use same predefined methods for the web services.
3. Simply it's a application as a server.

Above are the requirements, not sure how I can achieve it. Moreover, I need some details of "floreant pos" plugin architecture that they have released in 1.4 version so can anyone help on plugin architecture understanding of "floreant pos"..

Website :- http://floreant.org/ Wiki :- http://wiki.floreantpos.org/

I have been stuck for a long time. Please provide me some solution.

Thanks in advance