As part of looking at TUSCANY-1379 I've added a new webapp distribution module that supports using multiple SCA contribution jars and hot update of those jars so you can modify the contribution jar and the changes are picked up without having to restart the webapp. Its not in the build but you can manually build distribution/webapp (or there's a prebuilt war I'm using at http://people.apache.org/~antelder/tuscany/tuscany.war). Its also got a very trivial web interface that shows the current active components, go to: http://localhost:8080/tuscany/. To use it you just drop your SCA contribution jar's into the sca-contributions folder within the webapp and they should get picked up and installed right away, eg the Tuscany sample-calculator.jar or helloworld-ws-service.jar work. Once installed you can use something like winzip to edit the contents of the jar's and the changes should also get picked up.
Playing around with this highlights lots of problems, there's TODOs around the code about some of them, but one issue is the way the runtime and contribution service currently uses a single class loader so if you try to update and stop/start a single component or contribution the changes don't get picked without restarting the entire SCA domain to use a new class loader. I wondered if this class loader issue is something that might already be being looked at with all the other work going on right now in this area? ...ant