hibernate jpa: Session is closed!

Application is based on Spring 2.5.5 and hibernate 3.2.0 GA.

I have the following method in my DAO that gets MessageEntities attached to the specified User:

public MessageEntity findByUserId(int userId) {
      List<MessageEntity> result = (List<MessageEntity&开发者_JAVA技巧gt;) em.createNamedQuery(MessageEntity.Q_BY_USER_ID).setParameter("userId", userId).getResultList();
      if (!result.isEmpty()) {
         return result.get(0);
      } else {
         return null;
     }
}

I need to call this method from my integration test to check whether system's behaviour is valid. As long as this method is not transactional, all I get is org.hibernate.SessionException: Session is closed!. The easiest way to avoid this is to mark findByUserId method with @Transactional(readOnly = true). But as I understand, transaction management should be the duty of service tier to avoid unnecessary transactions creation. So, my question is: how can I properly get away from SessionException?

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You need to perform all your database actions within a transaction scope. As you identified its usually considered good design to let the service layer of your database model deal with transactions. The only constraint then becomes that you must invoke your service model to get within the transaction scope, which might be undesirable during test.

I would recommend to make use of the testing fascilites provided by spring. See 9.3.2.3 Transaction management

You could also manually create a transaction before testing your method, e.g., by

Session sess = factory.openSession();
Transaction tx = null;
// try catch 
tx = sess.beginTransaction();
findByUserId(userId);
tx.commit();
tx.rollBack();

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Put the following annotations on the top of your test class.

@RunWith(SpringJUnit4ClassRunner.class)
@Transactional
@ContextConfiguration(locations = "classpath:/META-INF/spring/applicationContext.xml")

Also I wouldn't worry about putting additional @Transactional in DAOs. Spring usually checks to see if you are already in a transaction (with in the same thread) before it creates another.

"But as I understand, transaction management should be the duty of service tier to avoid unnecessary transactions creation."

This is more of a design choice (Spring Roo for example violates this)

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You can use this annotation on your controller method:

@Transactional(readOnly = true)