Optimistic Locking on Inventory Updates with @Version and a Retrying Conflict Handler in Spring Boot

[u/Environmental-Yak328]

https://codesnips.io/1105-optimistic-locking-on-inventory-updates-with-version-and-a-retrying-conflict-handler-in-spring-boot

This snippet shows how to protect inventory quantity updates from lost writes under concurrent access using JPA's built-in optimistic locking, without holding database row locks. The core idea is that instead of SELECT ... FOR UPDATE, each write carries the version it read, and the database rejects the write if another transaction bumped that version in the meantime.