Não aparece nome das coluna no jTable

/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package Gui;

import Dao.UsuarioDao;
import com.towel.el.annotation.AnnotationResolver;
import com.towel.swing.table.ObjectTableModel;

import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JScrollPane;
import modelo.Usuario;

/**
 *
 * @author Wellyngton
 */
public class Listar extends javax.swing.JDialog {

    /**
     * Creates new form Listar
     */
    private AnnotationResolver resolver;
    private ObjectTableModel otm;
    private UsuarioDao dao;

    public Listar(java.awt.Frame parent, boolean modal) {
        super(parent, modal);
        initComponents();
        resolver = new AnnotationResolver(Usuario.class);
        otm = new ObjectTableModel(resolver, "nome,sobrenome,email,departamento");
        try {
            dao = new UsuarioDao();
            otm.setData(dao.listarTodasAsPessoaList());
            jTable1.setModel(otm);
        } catch (SQLException ex) {
            Logger.getLogger(Listar.class.getName()).log(Level.SEVERE, null, ex);
        }

    }


    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();

        setTitle("Consultar Funcionários");

        jTable1.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {
                {null, null, null, null}
            },
            new String [] {
                "Nome", "sobre nome", "email", "Departamento"
            }
        ) {
            boolean[] canEdit = new boolean [] {
                false, false, false, false
            };

            public boolean isCellEditable(int rowIndex, int columnIndex) {
                return canEdit [columnIndex];
            }
        });
        jTable1.setCellSelectionEnabled(true);
        jTable1.setEditingColumn(2);
        jTable1.setEditingRow(2);
        jTable1.getTableHeader().setReorderingAllowed(false);
        jScrollPane1.setViewportView(jTable1);
        jTable1.getColumnModel().getSelectionModel().setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
        if (jTable1.getColumnModel().getColumnCount() > 0) {
            jTable1.getColumnModel().getColumn(0).setResizable(false);
            jTable1.getColumnModel().getColumn(1).setResizable(false);
            jTable1.getColumnModel().getColumn(2).setResizable(false);
            jTable1.getColumnModel().getColumn(3).setResizable(false);
        }

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(31, 31, 31)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 539, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(51, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(35, 35, 35)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 385, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(37, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        


    // Variables declaration - do not modify                     
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;
    // End of variables declaration                   


}