the automatic module name that is created in Java 9 for the jul-to-slf4 jar is jul.to.slf4j@1.8.0-beta1. This contains the token to which is a reserved word in Java 9 so the generated name cannot be used in requires statements in modul-info.java files of projects using jul-to-slf4j and inhibits migration of projects to Java 9.

This should be modified by adding

Automatic-Module-Name: jul_to_slf4j

to the manifest for the archive.