As agreed this is a spike/proof of concept for using the @PreUpdate annotation to simplify the code in the entities.

I've tested it manually by updating the entityVersion in the database, then updating the entity and only attributes. In both instances the entityVersion is downgraded successfully.

I'd like to get feedback to this approach before I apply it to more entities. The three remaining calls to updateEntityVersion() are necessary when updating child tables (here: attributes).

This could be changed to Hibernate listener as shown in #9761 to avoid missing any call to that method. The downside is the additional technical obscurity of Hibernate listeners. While the effect used in #9761 couldn't be achieved in another way, calling this method three times per entity is IMHO tolerable. Therefore

This needs to be applied to roles as well. To void repeating the JavaDoc of updateEntityVersion(), it could be pulled to a superclass/interface JpaRootEntity that will be introduced in #9761.

Thanks you @ahus1 - this gets a +1 from me and in my opinion it is perfectly fine to explicitly call updateEntityVersion where needed as opposed to having a listener in place. If necessary we can always revisit this decision in the future and refactor all entities accordingly, but for now your proposal looks good to me.

Thank you @ahus1 for the investigation!
I am wondering if the approach sketched in 4c0bcee solves an independent issue (object state versioning rather than entity format versioning solved in this PR) and is needed anyway?

@hmlnarik - they solve two independent problems. While this solves the downgrading of the schema problem, the other PR solves a concurrent update of the row problem.

@hmlnarik - update to my previous comment: there's already issue #9874 to track the concurrency problem.

@sguilhen @vramik - finalized my changes and also implemented this for roles. Ready for final review. Build is still running.

reverting to draft status, will rework to use Hibernate API to align implementation with #9894

On hold until #9894 is merged.

This PR is now updated to use the Hibernate SPI to update the entity version. I tested it manually locally and an entity version is downgraded successfully from 2 to 1 even if only an attribute was changed.

I decided to keep the two listeners separate as they serve two different purposes. Please let me know if you want name changes on new methods and classes.

As the listeners are hibernate specific, I moved the two listeners to the hibernate package.

Please let me know what you think, @vramik and @sguilhen. Thanks!

Note: #9944 and #9943 should be merged first, this PR then probably needs a rebase.