Create a plugin module type that allows people to register beans inside Spring.

This would allow plugin authors to write their own manager classes that are injected into (and shared between) other modules. (So if you're writing a Foobar plugin, you could have a FoobarManager coordinating the FoobarMacro and FoobarListener)

Dependencies are a complication: what happens to those things dependent on the FoobarManager if the manager isn't available? What if the FoobarManager is disabled then re-enabled?

Perhaps dependent modules would define a resource:

<resource type="spring-bean" key="example.plugin:Bean">

Then when Bean is activated or deactivated, all modules that list it as a resource are also bounced?