Button_aula_03/11/2007

import java.awt.*;import javax.swing.*;import java.awt.event.*;public class Jan extends JFrame {            private JButton Okbton;            public Jan() {        this.setTitle("Janela");        this.setSize(300,300);        this.addWindowListener(new WindowAdapter() {            public void windowClosing(WindowEvent e) {                aoFecharJanela();                            }                                });                                this.setLayout(new BorderLayout());                Okbton = new JButton("OK");        Okbton.addActionListener(new ActionListener(){            public void actionPerformed(ActionEvent e) {                JOptionPane.showMessageDialog(null, "Pressionado", "Funcionou!", JOptionPane.WARNING_MESSAGE);                            }                                });                this.add(Okbton, BorderLayout.NORTH);        this.setVisible(true);    }    public static void aoFecharJanela(){        JOptionPane.showMessageDialog(null, "Janela encerrada!");        System.exit(0);    }        public static void main(String [] args) {        new Jan();    }}