Session s = HibernateUtil.getSession();       
s.beginTransaction();       
Criteria q = s.createCriteria( Person.class ).add( Restrictions.eq( "lastName", "Newman" ) );       
List l = q.list();
System.out.println(l.size());
s.getTransaction().rollback();

@Entity
@Table( name="qts_person" )
@Inheritance( strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn( name="person_class" )
public class Person  {
    private Long id;   
    private String lastName;

    @Id
    @GeneratedValue( strategy=GenerationType.AUTO, generator="SEQ_GEN" )   
    public Long getId() { return id; } 
    public void setId( Long in ) { id = in; }

    @Column( name="last_name", nullable=false )
    public String getLastName() { return lastName; }
    public void setLastName(String lastName) { this.lastName = (lastName != null)?lastName.trim():null; }
}

@Entity
@DiscriminatorValue( "User" )
public class User extends Person {

    private AuthUser authUser;

    public User() {}
   
    public User( AuthUser user ) {
        setAuthUser( user );
    }   
   
    @OneToOne
    @Fetch( FetchMode.JOIN)   
    @JoinColumn( name="authuser_auth_userid")       
    public AuthUser getAuthUser() {
        return authUser;
    }

    public void setAuthUser(AuthUser authUser) {
        this.authUser = authUser;
    }
}

@Entity
@Table( name="auth_users_data" )
public class AuthUser  {
    private Long _id;
   
    public AuthUser() {}

    @Id
    @Column( name="AUTH_USERID" )
    public Long getId() {
        return _id;
    }
   
    public void setId(Long id) {
        _id = id;
    }
}

Hibernate: select this_.id as id0_3_, this_.create_ts as create3_0_3_, this_.creator_id as creator10_0_3_, this_.updater_id as updater11_0_3_, this_.u
pdate_ts as update4_0_3_, this_.active as active0_3_, this_.first_name as first6_0_3_, this_.last_name as last7_0_3_, this_.middle_name as middle8_0_3
_, this_.email as email0_3_, this_.authuser_auth_userid as authuser12_0_3_, this_.person_class as person1_0_3_, person2_.id as id0_0_, person2_.create
_ts as create3_0_0_, person2_.creator_id as creator10_0_0_, person2_.updater_id as updater11_0_0_, person2_.update_ts as update4_0_0_, person2_.active
as active0_0_, person2_.first_name as first6_0_0_, person2_.last_name as last7_0_0_, person2_.middle_name as middle8_0_0_, person2_.email as email0_0
_, person2_.authuser_auth_userid as authuser12_0_0_, person2_.person_class as person1_0_0_, person3_.id as id0_1_, person3_.create_ts as create3_0_1_,
person3_.creator_id as creator10_0_1_, person3_.updater_id as updater11_0_1_, person3_.update_ts as update4_0_1_, person3_.active as active0_1_, pers
on3_.first_name as first6_0_1_, person3_.last_name as last7_0_1_, person3_.middle_name as middle8_0_1_, person3_.email as email0_1_, person3_.authuser
_auth_userid as authuser12_0_1_, person3_.person_class as person1_0_1_, authuser4_.AUTH_USERID as AUTH1_10_2_ from qts_person this_ inner join qts_per
son person2_ on this_.creator_id=person2_.id left outer join qts_person person3_ on person2_.updater_id=person3_.id left outer join auth_users_data au
thuser4_ on person3_.authuser_auth_userid=authuser4_.AUTH_USERID where this_.last_name=?
Hibernate: select authuser0_.AUTH_USERID as AUTH1_10_0_ from auth_users_data authuser0_ where authuser0_.AUTH_USERID=?
Hibernate: select authuser0_.AUTH_USERID as AUTH1_10_0_ from auth_users_data authuser0_ where authuser0_.AUTH_USERID=?
Hibernate: select authuser0_.AUTH_USERID as AUTH1_10_0_ from auth_users_data authuser0_ where authuser0_.AUTH_USERID=?

Criteria q = s.createCriteria( Person.class ).setFetchMode( "authUser", FetchMode.JOIN ).add( Restrictions.eq( "lastName", "Newman" ) );