Java - Strut2 e ivernate con 2 tablas

@Entity

@Table(name="trama", catalog="bd_1")

public class Trama  implements java.io.Serializable {

     private int traNoca;         //Int

     private int catNoca;       //Enlace con categoria

     private String tradat;       //Dato sin importancia

    public Trama() {}

    public Trama(int traNoca, int catNoca, String tradat)

    {this.traNoca = traNoca;  this.catNoca = catNoca;  this.tradat = tradat;  }

     @Id

    @Column(name="tra_noca", nullable=false)

     public int getTraNoca() {return this.traNoca;} ES

    public void setTraNoca(int traNoca) {this.traNoca = traNoca; }

    @Column(name="cat_noca", nullable=false)

    public int getCatNoca() {return this.catNoca;}

    public void setCatNoca(int catNoca) {this.catNoca = catNoca;}

    @Column(name="tra_dat", nullable=false, length=45)

    public String getTradat() {return this.tradat;}

    public void setTradat(String tradat) { this.tradat = tradat;  }

}

<hibernate-mapping>

    <class name="entidad.Trama" table="trama" catalog="bd_1">

        <id name="TraNoca" type="int">

            <column name="tra_noca" />

           <generator class="assigned"></generator>

        </id>

        <property  name="CatNoca" type="int">

            <column name="cat_noca" />

         </property>

        <property name="Tradat" type="string">

            <column name="cat_dat" length="50" />

        </property>

    </class>

</hibernate-mapping>

package entidad;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.Id;

import javax.persistence.Table;

@Entity

@Table(name = "trama", catalog = "bd_1"   )

public class Categoria  implements java.io.Serializable {

     private int catNoca;

     private String catNom;

    public Categoria() {}

    public Categoria(int catNoca, String catNom)

    {this.catNoca = catNoca;   this.catNom = catNom;}

     @Id

     @Column(name="cat_noca", nullable=false)

    public int getCatNoca() {return this.catNoca;}

    public void setCatNoca(int catNoca) {this.catNoca = catNoca;}

    @Column(name="cat_nom", nullable=false, length=45)

    public String getCatNom() {return this.catNom;}

    public void setCatNom(String catNom) { this.catNom = catNom; }

}

<hibernate-mapping>

    <class name="entidad.Categoria" table="categoria" catalog="bd_1">

        <id name="CatNoca" type="int">

            <column name="cat_noca" />

           <generator class="assigned"></generator>

        </id>

        <property name="CatNom" type="string">

            <column name="cat_nom" length="50" />

        </property>

    </class>

</hibernate-mapping>

public  void detalle2(String noca,T entity) {

        Session session = HibernateUtil.getSessionFactory().openSession();

        Transaction beginTransaction = session.beginTransaction();

        session.createSQLQuery("select c.CatNoca, c.CatNom, t.CatNoca, t.TraNoca, t.CatNom, t.tradat  from Trama t INNER JOIN Categoria c ON t.CatNoca="+entity);

        beginTransaction.commit();

        session.close();

	}

package acciones;

import static com.opensymphony.xwork2.Action.INPUT;

import static com.opensymphony.xwork2.Action.SUCCESS;

import com.opensymphony.xwork2.ActionSupport;

import entidad.Categoria;

import java.util.List;

import servicio.ServicioCategoria;

public class CategoriaAction extends ActionSupport {

    private ServicioCategoria sc= new ServicioCategoria();

    private List<Categoria> lstCat;

    private Categoria cat;

    private String m;//NO IMPORTANTE PARA LA DUDA

    private String i;//NO IMPORTANTE PARA LA DUDA

    private Integer noca;

    @Override

    public String input() throws Exception {

        if (getNoca()!=null) {setCat(sc.find(noca));}

        return INPUT;}

    public String detalle2() throws Exception {

        if (getNoca()!=null) {setCat(sc.find(noca)); }

       return INPUT;}

    @Override

    public String execute() throws Exception {return SUCCESS;}

    public String save() {    sc.save(getCat());     return "ok"; }

    public String remove(){    sc.remove(getNoca());    return "ok";    }

    public String list() throws Exception { lstCat=sc.findAll();  return execute();}

    public String search() throws Exception { lstCat = sc.search(m);return execute();}

    public String indice() throws Exception { lstCat = sc.search(i);return execute();}

    //<editor-fold defaultstate="collapsed" desc="Getter y Setter">  

    public ServicioCategoria getSc() {return sc; }

    public void setSc(ServicioCategoria sc) {this.sc = sc;}

    public String getM() { return m;}

    public void setM(String m) {   this.m = m; }

    public String getI() { return i; }

    public void setI(String i) { this.i = i;}

    public Integer getNoca() { return noca; }

    public void setNoca(Integer noca) {this.noca = noca;}

    public Categoria getCat() {return cat;}

    public void setCat(Categoria cat) { this.cat = cat; }

    public List<Categoria> getLstCat() {return lstCat;}

    public void setLstCat(List<Categoria> lstCat) {this.lstCat = lstCat;}

//</editor-fold>

}

public class ServicioCategoria extends AbstractFacade<Categoria> {

    public ServicioCategoria() {super(Categoria.class);}

    //CATEGORIA

    public List<Categoria> findAll() {return super.findAll();}

    public void save(Categoria cat) {super.createEdit(cat);}

    public void remove(int noca) {

        final Categoria find = super.find(noca);

        if (find!=null){

        super.remove(find);}

    }

    public Categoria find (int noca) {

        return super.find(noca);

    }

    //TRAMA   

}