Exibir um JCheckBox nas células de uma JTable

import javax.swing.*;
import java.awt.*;
import javax.swing.table.*;

public class Estudos extends JFrame{
  public Estudos(){
    super("Exemplo de uma tabela simples");
		     
    // constrói a tabela
    JTable tabela = new JTable(new Modelo());
    
    tabela.setPreferredScrollableViewportSize(new Dimension(350, 50));
	
    Container c = getContentPane();
    c.setLayout(new FlowLayout());
			
    JScrollPane scrollPane = new JScrollPane(tabela);
    c.add(scrollPane);
    	
    setSize(400, 300);
    setVisible(true);
  }
	
  public static void main(String args[]){
    Estudos app = new Estudos();
    app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
}

class Modelo extends AbstractTableModel {
  private String[] colunas = {"Nome", "Devedor"};
  private Object[][] conteudo = {
     {"Osmar J. Silva", new Boolean(true)},
     {"Fernando Santos", new Boolean(false)}
  };

  public int getColumnCount(){
    return colunas.length;
  }

  public int getRowCount(){
    return conteudo.length;
  }

  public String getColumnName(int col){
     return colunas[col];
  }

  public Object getValueAt(int row, int col){
    return conteudo[row][col];
  }

  public Class getColumnClass(int c){
    return getValueAt(0, c).getClass();
  }

  public boolean isCellEditable(int row, int col) {
    return true;
  }

  public void setValueAt(Object value, int row, int col) {
    conteudo[row][col] = value;
    fireTableCellUpdated(row, col);
  }
}