I have a structure like this: 
Code:
@Entity
public class User {
   Person person;
   //...
}
@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public abstract class Person {...}
@Entity
public class Student extends Person {
   SomeType someStudentProperty;
   //...
}
@Entity
public class Teacher extends Person {...}    
I want to query the users with testing the someStudentProperty in the where clause, but it doesn't work... 
"from User u where u.person.someStudentProperty = whatsoever..." 
("from User u where u.person.somePersonProperty = whatsoever..." works correctly) 
Is it a bug, I miss something, or it is not a supported feature?