Scenario: two callers load the same order (both see version N), the first saves
(version becomes N+1), then the second — still holding version N — tries to save.

result: org.springframework.dao.OptimisticLockingFailureException: Failed to update versioned entity with id '1' (version '0') in table ["JDBC_ORDER"]; Was the entity updated or deleted concurrently?

@Version on the JDBC side behaves the same as @Version under JPA: the UPDATE's
WHERE clause includes "and version = :expectedVersion", zero rows match, and
Spring Data JDBC turns that into OptimisticLockingFailureException rather than
silently doing nothing.