MCR-2647 hibernate 6 jpa 3.1

[yagee-de]

Link to jira.

[yagee-de]

Waits currently for fix of https://hibernate.atlassian.net/browse/HHH-15331

[yagee-de]

Ready for review!
Includes latest hibernate and H2 version
Tested with MyCoRe-Org/mir#907

[rsteph-de]

We have already MyCoRe applications, that are based the main branch / LTS 2023.06 and in production.
This change needs a migration guide and the merge should be announced on the developer's list.

As far as I can see, at least the persistence.xml changes. Anything else?

[yagee-de]

We have already MyCoRe applications, that are based the main branch / LTS 2023.06 and in production. This change needs a migration guide and the merge should be announced on the developer's list.

As far as I can see, at least the persistence.xml changes. Anything else?

Tested with postgres in mir-docker and this requires no migration, also those old properties (javax.* instead of jakarta.*) seems to work (but produce a warning).

For development environments this requires to migrate to a newer version of H2.

1. Use web console with your old version of h2
   java -jar h2-1.4.199.jar and connect to your database (same URI as in persistence.xml)
   export database to SQL file
   SCRIPT TO '/path/to/backup-1.4.sql'
   stop old H2 instance
2. Move or delete H2-Database directory
3. Create new database with version 2.2.x
4. Connect to new database (same steps as in 1. but with newer version of H2)
   RUNSCRIPT FROM '/path/to/backup-1.4.sql' FROM_1X
ALTER TABLE MCRUSERATTR ALTER COLUMN "VALUE" RENAME to "value"

[yagee-de]

Also note: If you have custom JQL queries in your code: They are validated more strictly and no "guessing" is done anymore in Hibernate 6.x. But all those obstacles in MyCoRe should be tackled in this PR.