Seam framework storing active user in session scobe - annotations

Question

I want to store activeUser object in session scobe when someone logged in, I am using it forward for user specific operations but there is a problem accours when admin attemps to loggin because admin is not a default user so #out annotation causes an error
error code is familiar = #Out attribute requires non-null value: authenticator.activeUser
my logic code is below;
(note: admin and standart user use same login panel)
#Out(scope = ScopeType.SESSION, required = true)
private User activeUser;
public boolean authenticate() throws Exception {
// SELECT OBJECT(user) FROM User user WHERE user.name = :name and
// user.password = :pass
try {
// create a query for getting a user with specified parameters if no
// user exist throw an exception
setActiveUser((User) entityManager
.createQuery(
"select u from User u where u.userName= :uname and u.password = :pass")
.setParameter("uname", credentials.getUsername())
.setParameter("pass", credentials.getPassword())
.getSingleResult());
identity.addRole("user");
return true;
} catch (Exception e) {
// so there is no any normal user now looking for any admin entry
System.out.println("there is no any member looking for admin");
try {
Admin admin = (Admin) entityManager
.createQuery(
"select a from Admin a where a.username = :uname and a.pass = :p")
.setParameter("uname", credentials.getUsername())
.setParameter("p", credentials.getPassword())
.getSingleResult();
identity.addRole("admin");
System.err.println("found admin");
return true;
} catch (Exception e2) {
System.err.println("admin bulunamadı");
throw e2;
}
}
}
in #out required must be true because in user specific crud operations I am logging them with user id.
how can I solve this problem. setting required=false is enough?
and the other hand if no user finds the entitymanager.resultlist() method throws an exception. so i know that the #out annotataions works unless the methods throw any excepttion?