I am trying the following hierarchy and I can get it to work when I run select's however, when I try to insert data, it fails with a Contraint Violation Exception. If I add a BaseContactVO it persists fine, but if I create a new ContactVO then it seems to want to add it twice to the same table and thus it creates a duplicate ID.... I was under the impression that this was possible, but maybe I am mistaken.

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
@Table(name = "rootobjects", catalog = "demo")
public abstract class RootObjectVO {

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@Table(name = "contacts", catalog = "demo")
public class BaseContactVO extends RootObjectVO {

@Entity
@Table(name = "contacts", catalog = "demo")
public class ContactVO extends BaseContactVO {

Has anyone else succeeded at something like this?

Thanks for the help,

Kevin