problemas con reflection

package app.contr.clases;
import app.model.api.*;
import app.contr.util.FacadeModel;
import app.model.concrete.UsuarioModel;
import java.sql.SQLException;
import java.util.*;
import up.max.proyectpages.structs.PagesList;
public class Usuario implements IPersSimple
{
    private int id;
    private String ci;
    private GregorianCalendar fecnac;
    private String nom1;
    private String nom2;
    private String ape1;
    private String ape2;
    private String pass;
    private Rol objr;
    protected final IModel im = FacadeModel.getInstance().createModel(this);
    @Override
    public int getId() {
        return id;
    }
    @Override
    public void setId(int id) {
        this.id = id;
    }
    @Sort(place = 0)
    public String getCi() {
        return ci;
    }
    public void setCi(String ci) {
        this.ci = ci;
    }
    @Sort(place = 1)
    public GregorianCalendar getFecnac() {
        return fecnac;
    }
    public void setFecnac(GregorianCalendar fecnac) {
        this.fecnac = fecnac;
    }
    @Sort(place = 2)
    public String getNom1() {
        return nom1;
    }
    public void setNom1(String nom1) {
        this.nom1 = nom1;
    }
    @Sort(place = 3)
    public String getNom2() {
        return nom2;
    }
    public void setNom2(String nom2) {
        this.nom2 = nom2;
    }
    @Sort(place = 4)
    public String getApe1() {
        return ape1;
    }
    public void setApe1(String ape1) {
        this.ape1 = ape1;
    }
    @Sort(place = 5)
    public String getApe2() {
        return ape2;
    }
    public void setApe2(String ape2) {
        this.ape2 = ape2;
    }
    @Sort(place = 6)
    public String getPass() {
        return pass;
    }
    public void setPass(String pass) {
        this.pass = pass;
    }
    @Sort(place = 7)
    public Rol getObjr() {
        return objr;
    }
    public void setObjr(Rol objr) {
        this.objr = objr;
    }
    public Usuario() {}

    public Usuario(int id, String ci, GregorianCalendar fecnac, String nom1, String nom2, String ape1, String ape2, String pass, Rol objr) {
        this.id = id;
        this.ci = ci;
        this.fecnac = fecnac;
        this.nom1 = nom1;
        this.nom2 = nom2;
        this.ape1 = ape1;
        this.ape2 = ape2;
        this.pass = pass;
        this.objr = objr;
    }
    @Override
    public boolean equals(Object obj) {
        if(obj instanceof Usuario){
            Usuario objp = (Usuario) obj;
            return objp.ci.equals(this.ci);
        } else {
            return false;
        }
    }
    @Override
    public int hashCode() {
        int hash = 7;
        hash = 59 * hash + Objects.hashCode(this.ci);
        return hash;
    }

    @Override
    public String toString() {
        String field = ape1 + " ";
        field += (ape1 != null) ? ape2 + " " : "";
        field += nom1 + " ";
        field += (nom2 != null) ? nom2 : "";
        return field;
    }

    @Override
    public void save() throws Exception {
        im.save(this);
    }
    @Override
    public void del() throws SQLException {
        im.del(this);
    }
    @Override
    public PagesList find(String[] criterios) throws SQLException {
        return im.find(criterios);
    }
    @Override
    public IPersistente findById(int id) throws SQLException {
        return im.findById(id);
    }
    @Override
    public int maxId() {
        return im.maxId();
    }
    @Override
    public IPersistente findByX(String x) throws SQLException {
        return im.findByX(x);
    }
    public IPersistente login(String login, String pass) throws SQLException{
        return ((UsuarioModel)im).login(login, pass);
    }
    @Override
    public boolean check() {
        return im.checkPersist();
    }
}

package app.contr.clases;
import app.model.api.Sort;
import java.util.GregorianCalendar;
public class Administrador extends Usuario
{
    public Administrador() { }
    public Administrador(int id, String ci, GregorianCalendar fecnac, String nom1, String nom2, String ape1, String ape2, String pass, Rol objr) {
        super(id, ci, fecnac, nom1, nom2, ape1, ape2, pass, objr);
    }
    @Sort(place = 0)
    public int getMe(){
        return this.getId();
    }
}

package app.contr.clases;
import app.model.api.Sort;
import java.util.GregorianCalendar;
public class Comprador extends Usuario
{
    private String categ;
    @Sort(place = 1)
    public String getCateg() {
        return categ;
    }
    public void setCateg(String categ) {
        this.categ = categ;
    }
    @Sort(place = 0)
    public int getMy() {
        return this.getId();
    }
    public Comprador() { }

    public Comprador(int id, String ci, GregorianCalendar fecnac, String nom1, String nom2, String ape1,
            String ape2, String pass, Rol objr,String categ) {
        super(id, ci, fecnac, nom1, nom2, ape1, ape2, pass, objr);
        this.categ = categ;
    }
}

package app.contr.clases;
import java.util.GregorianCalendar;
public class Subastador extends Usuario
{
    private String habil;
    public String getHabil() {
        return habil;
    }
    public void setHabil(String habil) {
        this.habil = habil;
    }
    public Subastador() { }

    public Subastador(int id, String ci, GregorianCalendar fecnac, String nom1, String nom2,
            String ape1, String ape2, String pass, Rol objr,String habil) {
        super(id, ci, fecnac, nom1, nom2, ape1, ape2, pass, objr);
        this.habil = habil;
    }

}