Why is the EntityManager in my GAE + Spring (+graniteds) project reset to null?

Question

Hi all,

I'm having a problem with autowiring my EntityManager. Actually at server startup I can see that the injection works ok, though when trying to use my EntityManager it appears to be null again.

@Component
public class DataDaoImpl {

protected EntityManager entityManager;

@Autowired
public void setEntityManager(EntityManager entityManager) {
    System.out.println("Injecting "+entityManager); //works!
    this.entityManager = entityManager; 
}       

public void createData(String key, String value) {
    System.out.println("In createData entityManager is "+entityManager);
    //entityManager null!?
...

Output:
Injecting org.datanucleus.store.appengine.jpa.DatastoreEntityManager@a60d19
The server is running at http://localhost:8888/
In createData entityManager is null

So somehow the autowired entityManager is reset to null when trying to use it. It's a graniteds powered project though I don't think this is graniteds related.

Any ideas?

Thanks a lot in advance,

Jochen