Guice @Transactional does not start an transaction

Question

I have started to use Guice method-level transactions like described here. I have a message like

@Inject
private EntityManager entityManager;

@Transactional
public UserSession createSession(User user, String browser) {
    UserSession session = new UserSession(user, browser);
    entityManager.persist(session);
}

From the short description i thought wis should be enough. But i get an error cause no transaction is started. It works only if i start and commit it by myself.

The Object is created by Guice on the Start of my Application in an initializer. the same Instance is used for each request.

Why is it not working?

Answer 1

@Transactional method annotations work through AOP, in which Guice fulfills a request for Foo by creating a proxy object that intercepts those annotated method calls and (optionally) forwards them to the actual object. Make sure that the following are true:

1. You have created the object with the @Transactional method through Guice, since Guice otherwise won't have any chance to provide the proxy instead.

2. Neither the class nor the method is marked final, since AOP can't override those easily.

3. You have installed JpaPersistModule, or some other form of PersistModule. Note from that source code that this module is actually what binds the MethodInterceptor to the @Transactional annotation.

If this doesn't fit your needs exactly, remember that you can always go with the AOP documentation to write your own method interceptor. Good luck!