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 looked at Grails and it seems to be very robust and Rails alike solution. Should I look at Spring? Or it will be an overkill for my use case?
I really like the Play! Framework. It's a java RESTful framework that is very easy to develop in.
The most notable of it's features, IMO, is that you don't have to restart the server every time you make a code change - which makes development run much more smoothly.
My best bet would be with Axi2's REST Support
You also have http://www.restlet.org/ and Play
I haven't used them though, but I like the idea of Play, Rails like framework for Java.
Though I have been using Grails a lot lately, I hesitate to recommend in this case. If you want to read more about what the Grails framework offers 'out-of-the-box', beyond RESTful URL mappings and core REST features, see refguide.
Sounds as though you have the web tier and components solidified and are just looking for Java (or Groovy-) based service and DAO components, to be made available to the client with a REST api.
In that case, rather than to recommend Grails, you might just encourage your server side developer(s) to install a lightweight framework in front of their POJO classes. Candidates for this I like are REST-lets and DWR direct web remoting. . .of course there are others but the concerns such as security and maturity, ease of use, etc. these are tops.
The following showcase illustrates what Spring MVC can do for developing REST-ful web applications and services: http://blog.springsource.com/2010/07/22/spring-mvc-3-showcase/