A Red Hat customer is running EAP7 that has Hibernate 5.0.x and at the beginning "2.8.12. Custom collection types" chapter 5.0.x documentation is introducing confusion and misunderstanding for him, as the custom collection types are introduced only after hibernate 5.2.x release.

"Hibernate uses its own collection implementations which are enriched with lazy-loading, caching or state change detection semantics. For this reason, persistent collections must be declared as an interface type. The actual interface might be java.util.Collection, java.util.List, java.util.Set, java.util.Map, java.util.SortedSet, java.util.SortedMap or even other object types (meaning you will have to write an implementation of org.hibernate.usertype.UserCollectionType)."