REST/JSON is pretty much regarded as the "tool of choice" for mobile devices working with back end services. Oracle Mobile Application Framework (MAF) supports SOAP/XML, REST/XML and REST/JSON, however our support for REST/JSON is currently more code-centric that the others. Whilst we are working on adding more declarative/framework support for REST/JSON, if you do need to implement this now, we've published an end-to-end tutorial to show how to work with REST/JSON web services from an Oracle MAF application.
Whilst this might look quite long winded for anyone new to the platform, what we have done in this tutorial is go through the effort of setting up supporting framework classes which will make this implementation work with your own specific use cases.