What if the smtp server of my Email account needs authentication?

Question

Following is a simple program for sending Email in a GUI without username and password.But I found that my smtp server needs authentication,so i can't send mail.Who can help me with this problem?i'll be very grateful.
import javax.mail.*;
import javax.mail.internet.*;
import java.util.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class SMTPClient extends JFrame {
private JButton sendButton = new JButton("Send Message");
private JLabel fromLabel = new JLabel("From: ");
private JLabel toLabel = new JLabel("To: ");
private JLabel hostLabel = new JLabel("SMTP Server: ");
private JLabel subjectLabel = new JLabel("Subject: ");
private JTextField fromField = new JTextField(40);
private JTextField toField = new JTextField(40);
private JTextField hostField = new JTextField(40);
private JTextField subjectField = new JTextField(40);
private JTextArea message = new JTextArea(40, 72);
private JScrollPane jsp = new JScrollPane(message);
public SMTPClient() {
super("SMTP Client");
Container contentPane = this.getContentPane();
contentPane.setLayout(new BorderLayout());
JPanel labels = new JPanel();
labels.setLayout(new GridLayout(4, 1));
labels.add(hostLabel);
JPanel fields = new JPanel();
fields.setLayout(new GridLayout(4, 1));
String host = System.getProperty("mail.host", "");
hostField.setText(host);
fields.add(hostField);
labels.add(toLabel);
fields.add(toField);
String from = System.getProperty("mail.from", "");
fromField.setText(from);
labels.add(fromLabel);
fields.add(fromField);
labels.add(subjectLabel);
fields.add(subjectField);
Box north = Box.createHorizontalBox();
north.add(labels);
north.add(fields);
contentPane.add(north, BorderLayout.NORTH);
message.setFont(new Font("Monospaced", Font.PLAIN, 12));
contentPane.add(jsp, BorderLayout.CENTER);
JPanel south = new JPanel();
south.setLayout(new FlowLayout(FlowLayout.CENTER));
south.add(sendButton);
sendButton.addActionListener(new SendAction());
contentPane.add(south, BorderLayout.SOUTH);
this.pack();
class SendAction implements ActionListener {
public void actionPerformed(ActionEvent evt) {
try {
Properties props = new Properties();
props.put("mail.host", hostField.getText());
Session mailConnection = Session.getInstance(props, null);
final Message msg = new MimeMessage(mailConnection);
Address to = new InternetAddress(toField.getText());
Address from = new InternetAddress(fromField.getText());
msg.setContent(message.getText(), "text/plain");
msg.setFrom(from);
msg.setRecipient(Message.RecipientType.TO, to);
msg.setSubject(subjectField.getText());
// This can take a non-trivial amount of time so
// spawn a thread to handle it.
Runnable r = new Runnable() {
public void run() {
try {
Transport.send(msg);
catch (Exception ex) {
ex.printStackTrace();
Thread t = new Thread(r);
t.start();
message.setText("");
catch (Exception ex) {
// I should really bring up a more specific error dialog here.
ex.printStackTrace();
public static void main(String[] args) {
SMTPClient client = new SMTPClient();
// Next line requires Java 1.3 or later. I want to set up the
// exit behavior here rather than in the constructor since
// other programs that use this class may not want to exit
// the application when the SMTPClient window closes.
client.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
client.show();
}

Answer 1

The answer is in the javadocs for the com.sun.mail.smtp package:
http://java.sun.com/products/javamail/javadocs/com/sun/mail/smtp/package-summary.html