Optimistic vs Pessimistic Locking in JPA.

1. Optimistic Locking

• Mechanism: Adds a @Version column to the entity.
• Logic: During update, Hibernate checks if the version is the same. If someone else updated it, it throws OptimisticLockException.
• Best For: High concurrency with low conflict (most users don't edit the same record at the same time).

2. Pessimistic Locking

• Mechanism: Uses DB level locks (SELECT FOR UPDATE).
• Logic: Blocks other transactions from reading/writing until yours is finished.
• Best For: Scenarios where data integrity is critical and conflicts are frequent.