Pessimistic Locking in Spring Data JDBC

Question

In my SeatDAO I declare a findAll method with derived query. The DAO looks like this:

public interface SeatDAO extends CrudRepository<SeatDTO, Integer> {

    @Lock(LockMode.PESSIMISTIC_READ)
    Collection<SeatDTO> findAll();

}

When I now start the spring boot application along the PostgreSQL database, it gives me these errors:

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'seatDAO' defined in demo.adapters.database.SeatDAO defined in @EnableJdbcRepositories declared on JdbcRepositoriesRegistrar.EnableJdbcRepositoriesConfiguration: Could not create query for public abstract java.util.Collection demo.adapters.database.SeatDAO.findAll(); Reason: No property 'findAll' found for type 'SeatDTO'

Caused by: org.springframework.data.repository.query.QueryCreationException: Could not create query for public abstract java.util.Collection demo.adapters.database.SeatDAO.findAll(); Reason: No property 'findAll' found for type 'SeatDTO'

Caused by: org.springframework.data.mapping.PropertyReferenceException: No property 'findAll' found for type 'SeatDTO'

When I leave out pessimistic locking on findAll by dropping @Lock, the application runs without any problems.

What is the problem here and how can I solve this?

Thank you in advance.

Answer 1

The core issue lies in the @Lock(LockMode.PESSIMISTIC_READ) annotation being incorrectly applied to the findAll() method. Spring Data JPA's @Lock annotation is intended for locking individual entity instances, not for locking entire query results. The framework is attempting to interpret findAll() as a property of the SeatDTO entity, leading to the

"No property 'findAll' found" error.

Remove the @Lock annotation from the findAll() method:

public interface SeatDAO extends CrudRepository<SeatDTO, Integer> {

    Collection<SeatDTO> findAll();

}

Alternatives for Pessimistic Locking:

Lock individual entities within a transaction:

Java - Inside a transactional context

for (SeatDTO seat : seatDAO.findAll()) {
    // Lock each seat individually
     transactionManager.lock(seat, LockMode.PESSIMISTIC_READ);
    // Perform operations on the locked seat
}