All modules in the server are now marked as private. This caused some problems due to Keycloak itself using these modules. The fix for that was to introduce a dependencies module which adds the services module (which in turn adds most other things). This cause another issue as the persistence.xml wasn't found. I couldn't find a way to have the jpa module private as well as loading persistence.xml from it using standard Persistence.createEntityManagerFactory. The solution to that was found in the PR we have to allow adding custom entities, which uses a different mechanism to load the EntityManagerFactory that allows specifying the ClassLoader.

Changes in https://github.com/keycloak/keycloak/pull/2511/files#diff-ecd3344fed68cc1f51c41c09711b7c60R43 if anyone is interested.