Concurrency Control in Java Persistence API (JPA) with Hibernate: Optimistic vs. Pessimistic Locking

In the context of Java Persistence API (JPA) and Hibernate, optimistic locking and pessimistic locking are two strategies used to handle concurrent access to database records by multiple users or threads. These locking mechanisms help ensure data consistency and prevent conflicts when multiple entities attempt to read or modify the same database records simultaneously.

Why Locking Necessary : Concurrent Data Access Problem Scenarios

1. Two or more users or threads read the same database record simultaneously and update it independently.

• Result: Only one of the updates is persisted, and the changes made by other transactions are lost.

2. One transaction updates a record, and another transaction reads the record before the first transaction commits its changes.

• Result: The second transaction reads uncommitted data, which may be rolled back later, leading to incorrect information.

3. A transaction reads a record, and another transaction modifies or deletes the same record before the first transaction completes

• Result: The first transaction encounters different data when it reads the same…