Nomes das colunas de uma JTable

package Clientes;

import java.awt.BorderLayout;
import java.awt.Container;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;

/**
 *
 * @author Administrador
 */
public class janelaCliente extends JDialog {
    
    /** Creates a new instance of janelaCliente */
    public janelaCliente(JFrame frame) {
        super(frame);
        this.iniciar();
     
    }
    
    private void iniciar(){
        this.setTitle("Cadastro de Clientes");
        this.setSize(500,350);
        this.setLocationRelativeTo(null); 
        JPanel p = new JPanel();
        p.add(this.tabela());
        Container container = getContentPane();
        container.setLayout(new BorderLayout());
        container.add(p, BorderLayout.CENTER);
   
        this.setVisible(true);
                
    }
    
    private JTable tabela(){
        Object [] colunas = {"Nome", "Last Name", "Desporto", "# de Years", "Vegetarian"};
        Object[][] dados ={ {"bla", "Campione", "Snowboarding",new Integer(5), new Boolean(false)},
                            {"Alison", "Huml", "Rowing", new Integer(3), new Boolean(true)},
                            {"Kathy", "Walrath", "Knitting", new Integer(2), new Boolean(false)},
                            {"Sharon", "Zakhour", "Speed reading", new Integer(20), new Boolean(true)},
                            {"Philip", "Milne", "Pool", new Integer(10), new Boolean(false)}}; 
        
        JTable tabela = new JTable ();
        tabela.setModel(new DefaultTableModel(dados,colunas));
        JScrollPane scrollPane = new JScrollPane(tabela);
        
        
        return tabela;
    }
    
}