I have an abstract 'folder' class with the following annotations

@Entity
@Table(name="folder")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(
 name="foldertype",
 length=50,
 discriminatorType=DiscriminatorType.STRING
)
@DiscriminatorValue("f")

and the following generatedValue annotation.

@Id @GeneratedValue(strategy=GenerationType.AUTO)

on my getId method.

I have two subclasses of the folder class RootFolder and YearFolder.
I continue to then create a RootFolder

RootFolder r = new RootFolder();
hsession.saveOrUpdate(r);

But when I look in the database the id generated is 0. So I'm not convinced that my auto generation annotation is working.

I then go to create the YearFolder with the following code:

Session hsession = HibernateUtil.getSessionFactory().getCurrentSession();
RootFolder rootFolder = (RootFolder)hsession.createQuery("from Folder").list().get(0);
YearFolder yearFolder = new YearFolder();
yearFolder.setYear(year);
yearFolder.setRootFolder(rootFolder);
rootFolder.addYearFolder(yearFolder);
hsession.save(rootFolder);

but this fails as is complains that there is an id clash with the following error. (because both Ids are zero)

a different object with the same identifier value was already associated with the session: [com.tier2.arena.domain.YearFolder#0])

I'm using MySQL and used the appropriate Dialect in the properties file.

Am I using GeneratedValue correctly?
Running 4.0.3sp1 and hibernate-annotations-3.2.0.CR1