One-to-many relationship with JDO in Google App Engine

Question

I've followed the GAE docs on setting up one-to-many relationship in JDO but I'm still having trouble in retrieving the collection data back. I have no problem getting the other non-collection fields back. Here are my classes:

@PersistenceCapable
public class User{

    @PrimaryKey
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    private Key key;

    @Persistent
    private String uniqueId;

    @Persistent
    private String email;

    @Persistent
    private List<Address> addresses = new ArrayList<Address>() ;
    ...
}


@PersistenceCapable
public class Phone{

    @PrimaryKey
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    private Key key;

    @Persistent
    private String number;
    ...
}


public class UserDaoImpl implements UserDao {


    public void insertUser(User user) {
        if(user.getKey() == null) {
            com.google.appengine.api.datastore.Key key = KeyFactory.createKey(User.class.getSimpleName(), user.getEmail());
            user.setKey(key);
        }
        PersistenceManager pm = PersistenceManagerWrapper.getPersistenceManager();
        notNull(user);
        try {
            pm.makePersistent(user);
        } finally {
            pm.close();
        }
    }

    @SuppressWarnings("unchecked")
    public User getUser(String uniqueId) {
        PersistenceManager pm = PersistenceManagerWrapper.getPersistenceManager();
        Query query = pm.newQuery(User.class);
        query.setFilter("uniqueId == uniqueIdParam");
        query.declareParameters("String uniqueIdParam");
        User user = null;
        try {
            List<User> users = (List<User>)(query.execute(uniqueId));
            //TODO abstract this
            if(users.size() > 0)
                user = users.get(0);
        } finally {
            pm.close();
        }
        return user;
    }
}


public class UserDaoImplTest {
 @Test
    public void getUserTest() {
        User user = createTestUser();
        assertNotNull("The user object should not be null", user);
        userDao.insertUser(user);

        User returnedUser = userDao.getUser(TEST_USER_ID);
        assertNotNull("The returnedUser object should not be null", returnedUser);
        Assert.assertPropertyEqualsExcludeProperties("User Object", user, returnedUser, "");

    }
}

When I run the test, all the properties for User is populated but the list of Phone if I get is empty.