org.springframework.dao.PessimisticLockingFailureException: could not execute statement; SQL [n/a]; nested exception is org.hibernate.PessimisticLockException: could not execute statement

In my personal perspective, the error message “org.springframework.dao.PessimisticLockingFailureException: could not execute statement; SQL [n/a]; nested exception is org.hibernate.PessimisticLockException: could not execute statement” indicates a problem related to pessimistic locking in a Spring application using Hibernate as the ORM (Object-Relational Mapping) framework.

This error suggests that a pessimistic lock couldn’t be acquired or executed successfully when trying to perform a database operation, and it’s occurring at the Hibernate layer. Pessimistic locking is used to prevent concurrent modifications to the same database record, ensuring data consistency in a multi-user environment.

To resolve this issue, you can consider the following steps:

1. Check Database Locking Configuration:
   Verify that your database and Hibernate configuration for pessimistic locking is set up correctly. Ensure that you’re using the appropriate isolation levels and locking strategies.
2. Check Transaction Management:
   Ensure that your transactions are managed properly. You might be attempting to acquire a pessimistic lock outside of a transactional context, which can lead to this error.
3. Check Database Connection:
   Make sure that your database connection is healthy and that there are no issues with the connection pool. Sometimes, database connection problems can lead to lock-related errors.
4. Review Your Code:
   Examine the code where this error is occurring. Ensure that you are properly handling transactions and lock acquisition. You may need to explicitly start and commit transactions if you’re not using Spring’s declarative transaction management.
5. Optimistic Locking:
   Consider whether optimistic locking might be a better approach for your use case. It’s often preferred over pessimistic locking because it allows for more concurrent access while still ensuring data integrity.
6. Logging and Debugging:
   Enable logging in your Spring and Hibernate configurations to get more detailed information about the error. This can help pinpoint the exact cause of the locking failure.
7. Check for Deadlocks:
   Investigate if there are any database deadlocks occurring, as they can lead to lock-related exceptions. Most databases provide tools to monitor and analyze deadlocks.

Here’s an example of how you can use Spring’s declarative transaction management to handle transactions:

import org.springframework.transaction.annotation.Transactional;

@Service
public class YourService {

    @Autowired
    private YourRepository yourRepository;

    @Transactional
    public void performDatabaseOperationWithLock() {
        // Your code to acquire a pessimistic lock and perform the database operation
        // Make sure this method is called within a transactional context.
    }
}

Remember to adjust the locking and transaction management configurations according to your specific use case and database requirements.