Rafael Winterhalter The Arquillian-based tests spin up a WF instance as the container. Hibernate is "installed" into that container using the hibernate-orm-modules artifact. I believe you will need to adjust the definition of that module to include a dependency on Byte Buddy. That should be accomplished by editing hibernate-orm-modules/src/main/modules/org/hibernate/core/module.xml. I'm just not sure if there is already a "Byte Buddy" module we can refer to. Sanne Grinovero, Gunnar Morling?