Using a typical JEE framework, how do I develop and deploy a service that can be called as a web service (with a WSDL interface), be invoked via JMS messages, or called directly from another service in the same container?

Here's some more context:

Currently I am responsible for a service (let's call it Service X) with the following properties:

• Interface definition is a human readable document kept up-to-date manually.
• Accepts HTTP form-encoded requests to a single URL.
• Sends plain old XML responses (no schema).
• Uses Apache to accept requests + a proprietary application server (not servlet or EJB based) containing all logic which runs in a seperate tier.
• Makes heavy use of a relational database.
• Called both by internal applications written in a variety of languages and also by a small number of third-parties.

I want to (or at least, have been told to!):

• Switch to a well-known (pref. open source) JEE stack such as JBoss, Glassfish, etc.

• Split Service X into Service A and Service B so that we can take Service B down for maintenance without affecting Service A. Note that Service B will depend on (i.e. need to make requests to) Service A.

• Make both services easier for third parties to integrate with by providing at least a WS-I style interface (WSDL + SOAP + XML + HTTP) and probably a JMS interface too. In future we might consider a more lightweight API too (REST + JSON? Google Protocol Buffers?) but that's a nice to have.

Additional consideration are:

• On a smaller deployment, Service A and Service B will likely to running on the same machine and it would seem rather silly for them to use HTTP or a message bus to communicate; better if they could run in the same container and make method calls to each other.

• Backwards compatibility with the existing ad-hoc Service X interface is not required, and we're not planning on re-using too much of the existing code for the new services.

• I'm happy with either contract-first (WSDL I guess) or (annotated) code-first development.

Apologies if my terminology is a bit hazy - I'm pretty experienced with Java and web programming in general, but am finding it quite hard to get up to speed with all this enterprise / SOA stuff - it seems I have a lot to learn! I'm also not very used to using a framework rather than simply writing code that calls some packages to do things.

I've got as far as downloading Glassfish, knocking up a simple WSDL file and using wsimport + a little dummy code to turn that into a WAR file which I've deployed.