Annotating a class both @MappedSuperclass and @Embeddable was never supported and only used to work by chance. With version 6.6 we started to explicitly validate this, and we opted to create a dedicated migration-guide entry to let users, who might have been taking advantage of this “workaround”, know that they will need to take action when upgrading.
The model below used to work in ORM 6.5 and below, but now fails in 6.6 and later with this exception:
Removing
@MappedSuperclass, we face a different exception:And with Hibernate ORM 7.0.0.Alpha3 it can even result in an NPE in some cases.
The model:
Reproducer:
for ORM 6.6 (fails)
for ORM 6.5 (works fine)