In my work, I have been using the convenient features provided by Spring Data JPA's JpaRepository for rapid development. However, when I attempted to call the following code for the first time, it resulted in a java.sql.SQLException.

The declaration of my Repository

import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.repository.ListCrudRepository;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public interface JpaResourceOwnershipRepository extends ListCrudRepository<ResourceOwnershipPO, String>, JpaSpecificationExecutor<ResourceOwnershipPO> {

    List<ResourceOwnershipPO> findAllByOwnershipPathStartingWith(String ownershipStartPath);
}

the logic of how I call JpaResourceOwnershipRepository

.........
    private final JpaResourceOwnershipRepository repository;

    public void delete(ResourceReference resourceReference) {
        Objects.requireNonNull(resourceReference);
        repository.delete(resourceReferenceSpec(resourceReference));
    }

    private Specification<ResourceOwnershipPO> resourceReferenceSpec(ResourceReference resourceReference) {
        return resourceReferenceSpec(resourceReference.resourceType(),
                (root, query, cb) -> cb.equal(root.get(resourceId), resourceReference.resourceId())
        );
    }
..........

The exception message "Connection is read-only. Queries leading to data modification are not allowed" indicates that a read-only transaction is in effect, even though you didn't explicitly declare any "read-only transactions" in your business code. Upon investigation, I discovered that Spring Data JPA, specifically within the org.springframework.data.repository.core.support.TransactionalRepositoryProxyPostProcessor.RepositoryAnnotationTransactionAttributeSource#computeTransactionAttribute method, obtains TransactionAttribute based on certain priorities. By default, it first checks whether your JpaResourceOwnershipRepository methods and classes have relevant transaction annotations. Then, it looks at the declarations in Spring Data JPA's SimpleJpaRepository class. Subsequently, I reviewed the source code for the corresponding method in SimpleJpaRepository. Please see the following code snippet:

SimpleJpaRepository source code

	@Override
	public long delete(Specification<T> spec) {

		CriteriaBuilder builder = this.entityManager.getCriteriaBuilder();
		CriteriaDelete<T> delete = builder.createCriteriaDelete(getDomainClass());

		if (spec != null) {
			Predicate predicate = spec.toPredicate(delete.from(getDomainClass()), null, builder);

			if (predicate != null) {
				delete.where(predicate);
			}
		}

		return this.entityManager.createQuery(delete).executeUpdate();
	}

Upon reaching this point, I wonder whether this method should have been annotated with @Transactional but it wasn't. The @Transactional annotation's default value for readOnly is false, and considering the semantics of the method name, "delete" is clearly a write operation. It should not use the default false value that be specified on SimpleJpaRepository class . To confirm my suspicion, I examined other methods in SimpleJpaRepository with deletion semantics, and I found that all the other methods have the @Transactional annotation, except for the one I am using. Is this intentional behavior, or is it indeed a bug?

SimpleJpaRepository source code

	@Transactional
	@Override
	public void deleteById(ID id) {

		Assert.notNull(id, ID_MUST_NOT_BE_NULL);

		findById(id).ifPresent(this::delete);
	}