Try to change the query to the following instead:
from person p where p.class='US' order by name, forename"
thank you for response. Unfortunatly your suggestion not bring the desired result.
On hibernate forum I found that absence Serializable can cause the problem, but the BaseEntity class that extends Person class implements serialisation.
I hope it's not a similar problem like http://www.jboss.com/index.html?module=bb&op=viewtopic&t=98829
Any other idea?
found out that I have to use the fully qualified name in query like
"from de.foo.ecp.model.Person p where p.class='US' order by name, forename"
But why. What is to do using only the entity name?