@Entity
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
@DiscriminatorColumn(name = "DTYPE",
      discriminatorType=DiscriminatorType.STRING)
@DiscriminatorValue("S")
@Table(name="SUPER")
public class SUPER {
   protected String dtype;
   protected String name;

    public SUPER() {
    }

    @Column(name="DTYPE", insertable = false, updatable= false) //varchar2(31) in Oracle
    public String getDtype() {...
    public void setDtype(String dtype) {...

    @Column(name="NAME") //varchar2(200) in Oracle
    public String getName() {...
    public void setName(String name) {..

    @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE,generator="SUPER_SEQ_GEN")
    @SequenceGenerator(name="SUPER_SEQ_GEN", sequenceName="SUPER_SEQ",initialValue=1,allocationSize=1)
    @Column(name = "ID", insertable = false, updatable = false)
    public int getId() {...
    public void setId(int id) {...
}

@Entity
@DiscriminatorValue("SUB1")
public class SUB1 extends SUPER{
   private SUPER supertype;
   
   public SUB1() {
   }

   @OneToOne
   @JoinColumn(name = "ID")
   public SUPER getSupertype() {
      return supertype;
   }

   public void setSupertype(SUPER supertype) {
      this.supertype = supertype;
   }

//INHERITED METHOD
   public String getName(){
      return name;
   }
   
   public void setName(String name){
      this.name = name;
   }
   String URI;
   
   @Column(name="URI")
   String getURI(){
      return URI;
   }
   
   void setURI(String uri){
      this.URI= uri;
   }

}

etc. on SUB2 and SUB3

SUPER i = new SUPER();
  Query t = getEm().createQuery("select i from SUPER i where ID=3");
  SUPER j = (SUPER)t.getSingleResult();