Is there dynamic module discovery in JDK9?

In the upcoming Java 9, is there a way to dynamically discover which modules are available?

E.g.:

1. Run some app with some module path
2. While the app is running, add a few more modules into the module path (e.g. copy into module directories)
3. From within the app, query "give me all available modules" (perhaps with a filter, such as those providing an alternate implementation of the same service)

I can't quite tell from the documentation.