Hibernate, triggers and yo-yo update

While using Hibernate to manage DB operations in your application you may also need to use triggers to perform specific updates directly inside DB. But if you're using both update methods it's essential to protect yourself against yo-yo effect.

Dreadful 'deleted entity passed to persist' exception

From time to time I encounter the following exception: 'javax.persistence.EntityNotFoundException: deleted entity passed to persist'. It's nasty because its stack trace doesn't suggest a source of the problem. Thankfully it's also very easy to fix.