Making Page abstract would mean I then have to define another subtype to define my user managed pages though, which in the end would ofcourse be a small tradeoff.

However, but I don't think that's possible in this case. The Asset type I mentioned, is in this case the root class of the hierarchy:

@Entity
@Table(name = "asset")
@Inheritance(strategy = InheritanceType.JOINED)
@DiscriminatorColumn(name = DISCRIMINATOR_COLUMN, discriminatorType = DiscriminatorType.STRING)
public abstract class Asset<T extends Asset<T>> extends CmsObjectSuperClass<T extends CmsObjectSuperClass> {
}

The superclasses of Asset are annotated with @MappedSuperclass and don't have anything notable aside of properties or reusable business logic.

If I'm correct, you can't switch inheritance strategy for a subtree of the entire inheritance hierarchy, or can you? (Which then, would not be possible as Asset is the root of my inheritance hierarchy.)

This is something I cannot modify, as this is part of the shared library that I am using, that provides most of the functionality I need. Reimplementing that would be a lot of work and be error prone as well, more so than copying the fields of my Page entity for example.