Hibernate cannot determine the target type for collections when using a wildcard in the collection generic type definition in a OneToMany relationship.
I had a related issue recently with hibernate-orm as you can see in this link: https://hibernate.atlassian.net/browse/HHH-9403

The exact message is:
Caused by: org.hibernate.AnnotationException: Collection has neither generic type or OneToMany.targetEntity()

The line where I found that the issue may be fixed is in the JavaReflectionManager