Mail program timing out to smtp.gmail.com

[Jon Camilleri]

Is it possible to update this code snippet, in order to reflect the authentication required by Gmail. When I run this program using smtp.gmail.com as an SMTP server, an error is reading java.net.ConnectException

 /**
   @author Cay Horstmann
   @version 1.10 2004-08-03
*/

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.net.*;
import java.io.*;
import javax.swing.*;

/**
   This program shows how to use sockets to send plain text
   mail messages.
*/
public class MailTest
{  
   public static void main(String[] args)
   {  
      JFrame frame = new MailTestFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setVisible(true);
   }
}

/**
   The frame for the mail GUI.
*/
class MailTestFrame extends JFrame
{  
   public MailTestFrame()
   {  
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
      setTitle("MailTest");

      setLayout(new GridBagLayout());

      // we use the GBC convenience class of Core Java Volume 1 Chapter 9
      add(new JLabel("From:"), new GBC(0, 0).setFill(GBC.HORIZONTAL));

      from = new JTextField(20);
      add(from, new GBC(1, 0).setFill(GBC.HORIZONTAL).setWeight(100, 0));

      add(new JLabel("To:"), new GBC(0, 1).setFill(GBC.HORIZONTAL));

      to = new JTextField(20);
      add(to, new GBC(1, 1).setFill(GBC.HORIZONTAL).setWeight(100, 0));

      add(new JLabel("SMTP server:"), new GBC(0, 2).setFill(GBC.HORIZONTAL));

      smtpServer = new JTextField(20);
      add(smtpServer, new GBC(1, 2).setFill(GBC.HORIZONTAL).setWeight(100, 0));
 
      message = new JTextArea();
      add(new JScrollPane(message), new GBC(0, 3, 2, 1).setFill(GBC.BOTH).setWeight(100, 100));

      comm = new JTextArea();
      add(new JScrollPane(comm), new GBC(0, 4, 2, 1).setFill(GBC.BOTH).setWeight(100, 100));

      JPanel buttonPanel = new JPanel();
      add(buttonPanel, new GBC(0, 5, 2, 1));

      JButton sendButton = new JButton("Send");
      buttonPanel.add(sendButton);
      sendButton.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {  
               new Thread(new 
                  Runnable()
                  {
                     public void run()
                     {   
                        comm.setText("");
                        sendMail();
                     }
                  }).start();
            }            
         });
   }

   /**
      Sends the mail message that has been authored in the GUI.
   */
   public void sendMail()
   {  
      try
      {  
         Socket s = new Socket(smtpServer.getText(), 25);

         InputStream inStream = s.getInputStream();
         OutputStream outStream = s.getOutputStream();

         in = new Scanner(inStream);         
         out = new PrintWriter(outStream, true /* autoFlush */);

         String hostName = InetAddress.getLocalHost().getHostName();

         receive();
         send("HELO " + hostName);
         receive();
         send("MAIL FROM: <" + from.getText() + ">");
         receive();
         send("RCPT TO: <" + to.getText() + ">");
         receive();
         send("DATA");
         receive();
         send(message.getText());
         send(".");
         receive();
         s.close();
      }
      catch (IOException e)
      {  
         comm.append("Error: " + e);
      }
   }

   /**
      Sends a string to the socket and echoes it in the
      comm text area.
      @param s the string to send.
   */
   public void send(String s) throws IOException
   {  
      comm.append(s);
      comm.append("\n");
      out.print(s.replaceAll("\n", "\r\n"));
      out.print("\r\n");
      out.flush();
   }

   /**
      Receives a string from the socket and displays it
      in the comm text area.
   */
   public void receive() throws IOException
   {
      if (in.hasNextLine());
      {
         String line = in.nextLine();
         comm.append(line);
         comm.append("\n");
      }
   }

   private Scanner in;
   private PrintWriter out;
   private JTextField from;
   private JTextField to;
   private JTextField smtpServer;
   private JTextArea message;
   private JTextArea comm;

   public static final int DEFAULT_WIDTH = 300;
   public static final int DEFAULT_HEIGHT = 300;  
}

Source Core Java Volume 2 (7th Edition)

Related links
1. Configuring other email clients (Gmail).
2. RFC 2183, updated by RFC 2184, and, RFC 2231.

[Rob Spoor]

Don't manually connect to an SMTP server, but use JavaMail instead. It's designed for this kind of thing, and if you search a bit you'll find plenty of examples about getting JavaMail to connect to Google.