对于一个非常简单的后端服务器，最好的Java RESTful框架是什么？

I need to develop a very thin shim for hadoop to be used together with Rails/Sinatra application. I'm a .Net developer and have a lot experience with Ruby. So what is the best framework to choose giving the fact it is needed for a very small project and it should provide RESTful web services.I need to develop a very thin shim for hadoop t