EntityManager.merge() issue: does not store to DB

Strange issue happened when tried to store some entity to database using entityManager.merge() or entityManager.persist() - code seemed to be working, but no data appeared in the database. Sample code for service class:

@Service("myService")

@Transactional

public class MyService {

    private EntityManager entityManager;

    @PersistenceContext

    public void setEntityManager(EntityManager entityManager) {

        this.entityManager = entityManager;

    }

    public void store(User u) {

             entityManager.merge(u);

    }

}

The issue had simple solution, so if you are experiencing troubles with EntityManager.merge() not updating database check your Spring configuration file for the following line, that enables @Transactional annotation support:

<tx:annotation-driven mode="proxy" transaction-manager="transactionManager"/>