Ejemplo del las instrucciones para mandar emails

package gui;
import java.awt.Color;
import java.util.*;

import javax.mail.*;
import javax.mail.internet.*;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JTextArea;
import javax.swing.JButton;

import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.SystemColor;

import javax.swing.ImageIcon;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class Prueba {

    private static String USER_NAME = "julio.unlp2010@gmail.com";  // GMail user name (just the part before "@gmail.com")
    private static String PASSWORD = " contraseña  "; // GMail password
    private static JTextField textFieldDestinatario;


    public static void main(String[] args) {


               JFrame jc = new JFrame();
               jc.addWindowListener(new WindowAdapter() {
                @Override
                public void windowClosing(WindowEvent arg0) {

                    System.exit(0);

                }
               });
               jc.getContentPane().setForeground(SystemColor.inactiveCaptionText);
               jc.setTitle("Despachador De Emails ");
               jc.getContentPane().setBackground(SystemColor.inactiveCaptionText);
               jc.setSize(700, 700);
               jc.getContentPane().setLayout(null);
               jc.setLocationRelativeTo(null);
               textFieldDestinatario = new JTextField();
               textFieldDestinatario.setBackground(Color.WHITE);
               textFieldDestinatario.setBounds(69, 127, 244, 20);
               jc.getContentPane().add(textFieldDestinatario);
               textFieldDestinatario.setColumns(10);

               JLabel lblDestinatarioDelMensaje = new JLabel("Destinatario del mensaje .");
               lblDestinatarioDelMensaje.setForeground(SystemColor.activeCaptionBorder);
               lblDestinatarioDelMensaje.setBackground(Color.LIGHT_GRAY);
               lblDestinatarioDelMensaje.setBounds(69, 102, 212, 14);
               jc.getContentPane().add(lblDestinatarioDelMensaje);

               final JTextArea textArea = new JTextArea();
               textArea.setBackground(Color.WHITE);
               textArea.setBounds(69, 252, 316, 154);
               jc.getContentPane().add(textArea);

               JLabel lblContenidoDelMensaje = new JLabel("Contenido del mensaje .");
               lblContenidoDelMensaje.setForeground(SystemColor.activeCaptionBorder);
               lblContenidoDelMensaje.setBackground(SystemColor.activeCaptionBorder);
               lblContenidoDelMensaje.setBounds(74, 227, 224, 14);
               jc.getContentPane().add(lblContenidoDelMensaje);

               JButton btnEnviar = new JButton("enviar");
               btnEnviar.setForeground(Color.DARK_GRAY);
               btnEnviar.setBackground(Color.WHITE);
               btnEnviar.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent arg0) {
                    // Se realiza el envio del mensaje.

                    if((textFieldDestinatario.getText().length()>0) &&(textArea.getText().length()>0)){

                    System.out.println(textFieldDestinatario.getText() );
                    System.out.println(textArea.getText() );

                    String from = USER_NAME;
                    String pass = PASSWORD;
                    String[] to = {  textFieldDestinatario.getText()  }; // list of recipient email addresses
                    String subject = "Sistemas ";
                    String body =  textArea.getText();
                    sendFromGMail(from, pass, to, subject, body);

                    }else { System.out.println("No existe campos. "); }

                }
               });
               btnEnviar.setBounds(69, 417, 89, 23);
               jc.getContentPane().add(btnEnviar);
               jc.setVisible(true);



                /**

                String from = USER_NAME;
                String pass = PASSWORD;
                String[] to = {"julio.unlp2010@gmail.com"  }; // list of recipient email addresses
                String subject = "Java send mail example";
                String body ="julio.unlp2010@gmail.com";
                sendFromGMail(from, pass, to, subject, body);

                    */


        }



    private static void sendFromGMail(String from, String pass, String[] to, String subject, String body) {

        JFrame x = new  JFrame();
        x.setVisible(true);
        x.setTitle("entro a la clase . ");
        x.setSize(200, 300);

        Properties props = System.getProperties();
        String host = "smtp.gmail.com";
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.user", "julio.unlp2010@gmail.com");

        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");
        Session session = Session.getDefaultInstance(props);
        MimeMessage message = new MimeMessage(session);

        try {

            message.setFrom(new InternetAddress(from));
            InternetAddress[] toAddress = new InternetAddress[to.length];

            // To get the array of addresses
            for( int i = 0; i < to.length; i++ ) {
                toAddress[i] = new InternetAddress(to[i]);
            }

            for( int i = 0; i < toAddress.length; i++) {
                message.addRecipient(Message.RecipientType.TO, toAddress[i]);

            }

            message.setSubject(subject);
            message.setText(body);


            // Acá es donde se el ejecutable se teniene .


            Transport transport = session.getTransport("smtp");

            JFrame j = new  JFrame();
            j.setVisible(true);
            j.setTitle(" Transport transport = session.getTransport(smtp);  ");
            j.setSize(200, 300);

            transport.connect(host, from, pass);

            transport.sendMessage(message, message.getAllRecipients());

            transport.close();


            // Genero una ventana para ver pudo enviar el emails.


        }
        catch (AddressException ae) {
            ae.printStackTrace();
        }
        catch (MessagingException me) {
            me.printStackTrace();
        }
    }
}