Facing with ObjectOptimisticLocking FailureException after migrating to Hibernate 6.6.2.Final

Is there an option to save new entities with already predefined ids and not get this exception?

If this is really something that you absolutely need, you can use a custom generator like shown in this example: hibernate-orm/hibernate-core/src/test/java/org/hibernate/orm/test/idgen/userdefined/SequenceOrAssignedGeneratorTest.java at 6.6 · hibernate/hibernate-orm · GitHub

Allowing to re-persist data that was previously removed could be sign of a defect in your application though, so be careful what you’re doing.