Using LevelChangePropagator in Logback configuration causes the following exception in a modular application:

Exception in thread "main" java.lang.IllegalAccessError: class ch.qos.logback.classic.jul.LevelChangePropagator (in module ch.qos.logback.classic) cannot access class java.util.logging.LogManager (in module java.logging) because module ch.qos.logback.classic does not read module java.logging

I'm not sure how the multi-release system works exactly, but the java.logging module is not present currently in the module-info file. As it only makes sense to require the module if the LevelChangePropagator is used (as far as I know, I don't believe the core of Logback Classic would require java.logging?), I'd imagine adding a requires static java.logging statement should be enough.

There is an open pull request for this issue, but it features a plain requires statement which forces the requirement for all users whether they need it or not.