How to design an enterprise application with many independent processes?

How should I design an application comprised of numerous (but identical) independent processes that need to communicate data to an enterprise application and be monitored and accessible by a web interface?

Here's a more concrete example in Java:

1. The independent processes are multiple instances of a standalone J2SE application that receives on initialization data about a "user" entity and then starts doing stuff regarding this "user" (this is an infinite process and so any batch sort of design would be wrong here and also similarly, the starting time of these processes is irrelevant)

2. The enterprise application is a set of J2EE beans and web-services that implement business logic, DB access etc.. and that are (for example) hosted on GlassFish.

3. The web front is a set of JSPs (perhaps also on GlassFish) that work with the beans.

Now ideally, I want a way for the processes in (1) to be able to invoke methods from the beans in (2), but also for the beans in (2) to be able and update the processes (1) about things.

So these are the required flows of executions, assuming there are 10 independent process of (1) running for 10 different users (consider a "user" something easily identifiable by, say, a number):

• Something happens in one of the processes of (1) and they invoke a method from the enterprise application (2) with some data.
• One of the real, human, users (which was already identified by the web app) clicks something on a web-page of (3), this invokes a method in (2), and then some "magical" entity (which I have no idea how to name) finds the independent process from (1) that is responsible for this particular user and updates the process with some new data.

My best approach so far is to expose these J2SE apps by JMX and go from there, but I have one thing I don't understand - who or what should be holding a key-pair list of the sort "the process at URI X is responsible for user Y" and then directing the calls accordingly.

BTW, please feel free to give any advice outside of the Java platform (!), as long as it is a platform that can be scaled easily.

EDIT: Also, is there a way to "host" such independent processes on some app-server? Something that will re-spawn processes if they fail, allow for deployment and monitoring of such processes on remote machines etc.?