How to use java to send emails

Question

Hi,
I am having problems trying to send an email using java. No idea what is going on because it looks fine. Can anyone give any insight?
Cheers
Robert
import java.awt.event.*;
import java.awt.*;
import java.net.*;
import java.io.*;
import javax.swing.*;
* JEmail.java
* @author Robert Venning 18/09/2005
* @version 1.0
public class JEmail extends JFrame implements ActionListener{
     private static final long serialVersionUID = 1L;
     final int SMTP_PORT = 25;
     JLabel fromLabel = new JLabel("From: ");
     JLabel toLabel = new JLabel("To: ");
     JLabel ccLabel = new JLabel("CC: ");
     JLabel subjectLabel = new JLabel("Subject: ");
     JTextField from = new JTextField(20);
     JTextField to = new JTextField(20);
     JTextField cc = new JTextField(20);
     JTextField subject = new JTextField(20);
     JTextArea message = new JTextArea(10,30);
     JScrollPane scrollPane = new JScrollPane(message);
     JButton send = new JButton("Send");
     public JEmail(){
          super("Email Program");
          JPanel mainPane = new JPanel();
          JPanel pane = new JPanel();
          JPanel fromPane = new JPanel();
          JPanel toPane = new JPanel();
          JPanel ccPane = new JPanel();
          JPanel subjectPane = new JPanel();
          mainPane.setLayout(new FlowLayout());
          pane.setLayout(new GridLayout(4,1));
          fromPane.add(fromLabel);
          fromPane.add(from);
          toPane.add(toLabel);
          toPane.add(to);
          ccPane.add(ccLabel);
          ccPane.add(cc);
          subjectPane.add(subjectLabel);
          subjectPane.add(subject);
          pane.add(fromPane);
          pane.add(toPane);
          pane.add(ccPane);
          pane.add(subjectPane);
          mainPane.add(pane);
          mainPane.add(scrollPane);
          mainPane.add(send);
          setContentPane(mainPane);
          send.addActionListener(this);
     public static void main(String[] args) {
          JFrame aFrame = new JEmail();
          aFrame.setSize(350, 400);
          aFrame.setVisible(true);
     public void actionPerformed(ActionEvent event){
          try{
               PrintWriter writer = new PrintWriter(new FileWriter("log.txt"));
               String input, output;
               Socket s = new Socket("mail.tpg.com.au", SMTP_PORT);
               BufferedReader in = new BufferedReader
                    (new InputStreamReader(s.getInputStream()));
               BufferedWriter out = new BufferedWriter
          (new OutputStreamWriter(s.getOutputStream()));
               output = "HELO theWorld" + "\n";
               out.write(output);
               out.flush();
               System.out.print(output);
               writer.println(output);
               input = in.readLine();
               System.out.println(input);
     //          writer.println(input);
               output = "MAIL FROM: <" + from.getText() + ">" + "\n";
               out.write(output);
               out.flush();
               System.out.print(output);
               writer.println(output);
               input = in.readLine();
               System.out.println(input);
     //          writer.println(input);
               output = "RCPT TO: <" + to.getText() + ">" + "\n";
               out.write(output);
               out.flush();
               System.out.print(output);
               writer.println(output);
               input = in.readLine();
               System.out.println(input);
          //     writer.println(input);
               output = "DATA" + "\n";
               out.write(output);
               out.flush();
               System.out.print(output);
               writer.println(output);
               input = in.readLine();
               System.out.println(input);
          //     writer.println(input);
               output = "Subject: " + subject.getText() + "\n";
               out.write(output);
               out.flush();
          System.out.print(output);
          writer.println(output);
          output = "From: Robert Venning <" + from.getText() + ">" + "\n";
               out.write(output);
               out.flush();
          System.out.print(output);
          writer.println(output);
               // message body
          output = message.getText() + "\n";
               out.write(output);
               out.flush();
               System.out.print(output);
               writer.println(output);
               output = ".\n";
               out.write(output);
               out.flush();
               System.out.println(output);
               writer.println(output);
               output = "QUIT" + "\n";
               out.write(output);
               out.flush();
               System.out.print(output);
               writer.println(output);
               input = in.readLine();
               System.out.println(input);
     //          writer.println(input);
               writer.close();
               s.close();
          catch(Exception exception){
               exception.printStackTrace();
}

Answer 1

Hi, floppit. For sending emails, I used the JavaMail API. Here is some code I wrote where I used JavaMail. The most relevant lines are in bold.
/*   File:  ListenNotifier.java
* Author:  Fabricio Machado
*          [email protected]
* This utility is based on the "Listen.java" tool from the Tiny OS
* java tools package, in /tinyos-1.x/tools/java/net/tinyos/tools/.
* The original application has been extended to convert raw packet data into
* a more meaningful representation of actual photo sensor readings in
* lux.
* The application checks the readings against a user-defined
* threshold, and sends email notifications when readings break the
* threshold, and also when readings dip back below the threshold.
* Currently, the code is only fit to handle packets from the Tiny OS
* nesc application OscilloscopeRF.nc.  The code gets the packet data
* by connecting via TCP to a Tiny OS java tool called "Serial Forwarder."
* "Serial Forwarder" takes packets from the base station, and forwards
* them to TCP port 9001.
* Below is UC Berkeley's copyright disclaimer regarding the original code.
*                              |   |
*                              |   |
*                              |   |
*                              |   |
*                            __|   |__
*                                v
* "Copyright (c) 2000-2003 The Regents of the University  of California. 
* All rights reserved.
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without written agreement is
* hereby granted, provided that the above copyright notice, the following
* two paragraphs and the author appear in all copies of this software.
* IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
* CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
* THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS."
* Copyright (c) 2002-2003 Intel Corporation
* All rights reserved.
* This file is distributed under the terms in the attached INTEL-LICENSE    
* file. If you do not find these files, copies can be found by writing to
* Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300, Berkeley, CA,
* 94704.  Attention:  Intel License Inquiry.
import java.util.Properties;
import java.io.*;
import java.net.*;
import net.tinyos.packet.*;
import net.tinyos.util.*;
import net.tinyos.message.*;
import javax.mail.internet.*;
import javax.mail.*;
import java.util.*;
public class ListenNotifier{
    public static void main(String args[]) throws IOException, MessagingException {
     int i;
     int j = 0;
     Integer threshold=0;
     String to="";
     String timeStamp;
     // Check to see if user is running the program correctly.
     // If -T option is not used, a default value of 250 lux is
        // set as threshold . . .
     switch (args.length){
     case 0:
           System.err.println("usage: java ListenNotifier < EmailAddress1 > <  EmailAddress2 > . . .  -T < Threshold >\n");
           System.exit(2);
           break;
     case 1:
         to = args[j];
         threshold = 250;
         break;
     default:
         if (args[args.length-2].equals("-T")){
          threshold = threshold.valueOf(args[args.length-1]);
          to = args[0];
          while(!args[j+1].equals("-T")){
              to = to + " " + args[j+1];
              j++;
          break;
         else{
          j = 0;
          threshold = 250;
          to = args[j];
          while((j + 1) < args.length){
              to = to + " " + args[j+1];
              j++;
          System.out.printf("Mailing list is: %s\n", to);
          break;
     // Connect to the Serial Forwarder on TCP port 9001 . . .
         PacketSource reader = BuildSource.makeSF("192.168.0.12",9001);
     // Check to see if connection to Serial Forwarder successful . . .
     if (reader == null) {
         System.err.println("Invalid packet source (check your MOTECOM environment variable)");
         System.exit(2);
     try {
         // Use JavaMail API methods to set up an
         // email session . . .
      Properties props = System.getProperties();
     Session session = Session.getInstance(props, null);
     javax.mail.Message message = new MimeMessage(session);
         // Open the packet source . . .
         reader.open(PrintStreamMessenger.err);
         // Set a threshold boolean to be used so
         // email is sent only once after threshold
         // is exceeded.
         Boolean limit = false;
         for (;;) {
          // The node ID field in the OscilloscopeRF packet
          // is 2 bytes long, but all byte pairs in the packet
          // are in little endian order.  Thus, the bytes must
          //  be re-ordered.  They are then converted to unsigned
          // integers and added together to obtain the node ID.
          byte[] packet = reader.readPacket();
          Integer nodeID = (( int ) packet[5] & 0xFF) + ((( int ) packet[6] & 0xFF)<<8);
          System.out.printf("Packet from node %d . . . \n", nodeID);
          // Begin extracting data payload of sensor readings,
                // which are stored in the last 20 bytes of the packet . . .
         for (i = 0; i <= 9; i++){
          // Convert reading to integer, display on screen . . .
          Integer sensorData = (( int ) packet[(2*i)+11] & 0xFF) + ((( int ) packet[(2*i)+12] & 0xFF)<<8);
          System.out.printf("Sample %d reading at %d lux.\n", i+1, sensorData);
          // Is sensor reading  above limit?
          if(!limit && (sensorData >= threshold)){
              limit = true;
              System.out.printf("WARNING: SENSOR READING ABOVE THRESHOLD--SENDING NOTICE BY TEXT MESSAGE.\n");
              // Compute a time stamp for when threshold was exceeded.
              java.util.Locale locale = Locale.getDefault();
              java.text.DateFormat dateFormat = java.text.DateFormat.getDateTimeInstance(java.text.DateFormat.LONG,
                                                              java.text.DateFormat.LONG, locale);
              timeStamp = dateFormat.format(new java.util.Date());
              // Build message and send to recipients in mailing list . . .
              message.setFrom();
          message.setRecipients(javax.mail.Message.RecipientType.TO, InternetAddress.parse(to, false));
          message.setSubject("WARNING: NODE " + nodeID.toString() + " SENSOR READING ABOVE THRESHOLD!");
          message.setText("Node " + nodeID.toString() + " sensed " + sensorData.toString() + " lux on " + timeStamp + "\n");
          Transport.send(message);
              System.out.printf("%s\n",timeStamp);
          //  Has sensor reading now dropped from above threshold to below threshold?
          //  Same concept as before . . .
          if(limit && (sensorData < threshold)){
              limit = false;
              System.out.printf("READING BELOW THRESHOLD AGAIN . . . SENDING NOTICE BY TEXT MESSAGE.\n");
              java.util.Locale locale = Locale.getDefault();
              java.text.DateFormat dateFormat = java.text.DateFormat.getDateTimeInstance(java.text.DateFormat.LONG,
                                                              java.text.DateFormat.LONG, locale);
              timeStamp = dateFormat.format(new java.util.Date());
              message.setFrom();
          message.setRecipients(javax.mail.Message.RecipientType.TO, InternetAddress.parse(to, false));
          message.setSubject("NODE " + nodeID.toString() + " READING BELOW THRESHOLD AGAIN.");
          message.setText("Node " + nodeID.toString() + " sensed " + sensorData.toString() + " lux on " + timeStamp + "\n");
          Transport.send(message);
              System.out.printf("%s\n",timeStamp);
         System.out.println();
         System.out.flush();
     // Catch IOException from Tiny OS java method, and
     // MessagingException from setRecipients method in JavaMail API . . .
     catch (IOException e) {
         System.err.println("Error on " + reader.getName() + ": " + e);
     catch(MessagingException e){
     System.err.println("Error in javax.mail.message.setRecipients:\n" + to);
}