package net.codejava.swing.mail; import java.awt.Font; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.Insets; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.File; import java.util.Properties; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; import javax.swing.JOptionPane; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.JTextField; import javax.swing.SwingUtilities; import javax.swing.UIManager; import net.codejava.swing.JFilePicker; /** * A Swing application that allows sending e-mail messages from a SMTP server. * @author www.codejava.net * */ public class SwingEmailSender extends JFrame { private ConfigUtility configUtil = new ConfigUtility(); private JMenuBar menuBar = new JMenuBar(); private JMenu menuFile = new JMenu(\"File\"); private JMenuItem menuItemSetting = new JMenuItem(\"Settings..\"); private JLabel labelTo = new JLabel(\"To: \"); private JLabel labelSubject = new JLabel(\"Subject: \"); private JTextField fieldTo = new JTextField(30); private JTextField fieldSubject = new JTextField(30); private JButton buttonSend = new JButton(\"SEND\"); private JFilePicker filePicker = new JFilePicker(\"Attached\", \"Attach File...\"); private JTextArea textAreaMessage = new JTextArea(10, 30); private GridBagConstraints constraints = new GridBagConstraints(); public SwingEmailSender() { super(\"Swing E-mail Sender Program\"); // set up layout setLayout(new GridBagLayout()); constraints.anchor = GridBagConstraints.WEST; constraints.insets = new Insets(5, 5, 5, 5); setupMenu(); setupForm(); pack(); setLocationRelativeTo(null); // center on screen setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } private void setupMenu() { menuItemSetting.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent event) { SettingsDialog dialog = new SettingsDialog(SwingEmailSender.this, configUtil); dialog.setVisible(true); } }); menuFile.add(menuItemSetting); menuBar.add(menuFile); setJMenuBar(menuBar); } private void setupForm() { constraints.gridx = 0; constraints.gridy = 0; add(labelTo, constraints); constraints.gridx = 1; constraints.fill = GridBagConstraints.HORIZONTAL; add(fieldTo, constraints); constraints.gridx = 0; constraints.gridy = 1; add(labelSubject, constraints); constraints.gridx = 1; constraints.fill = GridBagConstraints.HORIZONTAL; add(fieldSubject, constraints); constraints.gridx = 2; constraints.gridy = 0; constraints.gridheight = 2; constraints.fill = GridBagConstraints.BOTH; buttonSend.setFont(new Font(\"Arial\", Font.BOLD, 16)); add(buttonSend, constraints); buttonSend.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent event) { buttonSendActionPerformed(event); } }); constraints.gridx = 0; constraints.gridy = 2; constraints.gridheight = 1; const.

1. package net.codejava.swing.mail;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.util.Properties;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import net.codejava.swing.JFilePicker;
/**
* A Swing application that allows sending e-mail messages from a SMTP server.
* @author www.codejava.net
*
*/
public class SwingEmailSender extends JFrame {
private ConfigUtility configUtil = new ConfigUtility();
private JMenuBar menuBar = new JMenuBar();
private JMenu menuFile = new JMenu("File");
private JMenuItem menuItemSetting = new JMenuItem("Settings..");
private JLabel labelTo = new JLabel("To: ");

2. private JLabel labelSubject = new JLabel("Subject: ");
private JTextField fieldTo = new JTextField(30);
private JTextField fieldSubject = new JTextField(30);
private JButton buttonSend = new JButton("SEND");
private JFilePicker filePicker = new JFilePicker("Attached", "Attach File...");
private JTextArea textAreaMessage = new JTextArea(10, 30);
private GridBagConstraints constraints = new GridBagConstraints();
public SwingEmailSender() {
super("Swing E-mail Sender Program");
// set up layout
setLayout(new GridBagLayout());
constraints.anchor = GridBagConstraints.WEST;
constraints.insets = new Insets(5, 5, 5, 5);
setupMenu();
setupForm();
pack();
setLocationRelativeTo(null); // center on screen
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private void setupMenu() {
menuItemSetting.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
SettingsDialog dialog = new SettingsDialog(SwingEmailSender.this, configUtil);
dialog.setVisible(true);
}
});

3. menuFile.add(menuItemSetting);
menuBar.add(menuFile);
setJMenuBar(menuBar);
}
private void setupForm() {
constraints.gridx = 0;
constraints.gridy = 0;
add(labelTo, constraints);
constraints.gridx = 1;
constraints.fill = GridBagConstraints.HORIZONTAL;
add(fieldTo, constraints);
constraints.gridx = 0;
constraints.gridy = 1;
add(labelSubject, constraints);
constraints.gridx = 1;
constraints.fill = GridBagConstraints.HORIZONTAL;
add(fieldSubject, constraints);
constraints.gridx = 2;
constraints.gridy = 0;
constraints.gridheight = 2;
constraints.fill = GridBagConstraints.BOTH;
buttonSend.setFont(new Font("Arial", Font.BOLD, 16));
add(buttonSend, constraints);
buttonSend.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
buttonSendActionPerformed(event);
}
});

4. constraints.gridx = 0;
constraints.gridy = 2;
constraints.gridheight = 1;
constraints.gridwidth = 3;
filePicker.setMode(JFilePicker.MODE_OPEN);
add(filePicker, constraints);
constraints.gridy = 3;
constraints.weightx = 1.0;
constraints.weighty = 1.0;
add(new JScrollPane(textAreaMessage), constraints);
}
private void buttonSendActionPerformed(ActionEvent event) {
if (!validateFields()) {
return;
}
String toAddress = fieldTo.getText();
String subject = fieldSubject.getText();
String message = textAreaMessage.getText();
File[] attachFiles = null;
if (!filePicker.getSelectedFilePath().equals("")) {
File selectedFile = new File(filePicker.getSelectedFilePath());
attachFiles = new File[] {selectedFile};
}
try {
Properties smtpProperties = configUtil.loadProperties();
EmailUtility.sendEmail(smtpProperties, toAddress, subject, message, attachFiles);
JOptionPane.showMessageDialog(this,

5. "The e-mail has been sent successfully!");
} catch (Exception ex) {
JOptionPane.showMessageDialog(this,
"Error while sending the e-mail: " + ex.getMessage(),
"Error", JOptionPane.ERROR_MESSAGE);
}
}
private boolean validateFields() {
if (fieldTo.getText().equals("")) {
JOptionPane.showMessageDialog(this,
"Please enter To address!",
"Error", JOptionPane.ERROR_MESSAGE);
fieldTo.requestFocus();
return false;
}
if (fieldSubject.getText().equals("")) {
JOptionPane.showMessageDialog(this,
"Please enter subject!",
"Error", JOptionPane.ERROR_MESSAGE);
fieldSubject.requestFocus();
return false;
}
if (textAreaMessage.getText().equals("")) {
JOptionPane.showMessageDialog(this,
"Please enter message!",
"Error", JOptionPane.ERROR_MESSAGE);
textAreaMessage.requestFocus();
return false;
}
return true;
}

6. public static void main(String[] args) {
// set look and feel to system dependent
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
ex.printStackTrace();
}
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new SwingEmailSender().setVisible(true);
}
});
}
}
Solution
package net.codejava.swing.mail;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.util.Properties;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;

7. import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import net.codejava.swing.JFilePicker;
/**
* A Swing application that allows sending e-mail messages from a SMTP server.
* @author www.codejava.net
*
*/
public class SwingEmailSender extends JFrame {
private ConfigUtility configUtil = new ConfigUtility();
private JMenuBar menuBar = new JMenuBar();
private JMenu menuFile = new JMenu("File");
private JMenuItem menuItemSetting = new JMenuItem("Settings..");
private JLabel labelTo = new JLabel("To: ");
private JLabel labelSubject = new JLabel("Subject: ");
private JTextField fieldTo = new JTextField(30);
private JTextField fieldSubject = new JTextField(30);
private JButton buttonSend = new JButton("SEND");
private JFilePicker filePicker = new JFilePicker("Attached", "Attach File...");
private JTextArea textAreaMessage = new JTextArea(10, 30);
private GridBagConstraints constraints = new GridBagConstraints();
public SwingEmailSender() {
super("Swing E-mail Sender Program");
// set up layout

8. setLayout(new GridBagLayout());
constraints.anchor = GridBagConstraints.WEST;
constraints.insets = new Insets(5, 5, 5, 5);
setupMenu();
setupForm();
pack();
setLocationRelativeTo(null); // center on screen
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private void setupMenu() {
menuItemSetting.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
SettingsDialog dialog = new SettingsDialog(SwingEmailSender.this, configUtil);
dialog.setVisible(true);
}
});
menuFile.add(menuItemSetting);
menuBar.add(menuFile);
setJMenuBar(menuBar);
}
private void setupForm() {
constraints.gridx = 0;
constraints.gridy = 0;
add(labelTo, constraints);
constraints.gridx = 1;
constraints.fill = GridBagConstraints.HORIZONTAL;
add(fieldTo, constraints);
constraints.gridx = 0;
constraints.gridy = 1;

9. add(labelSubject, constraints);
constraints.gridx = 1;
constraints.fill = GridBagConstraints.HORIZONTAL;
add(fieldSubject, constraints);
constraints.gridx = 2;
constraints.gridy = 0;
constraints.gridheight = 2;
constraints.fill = GridBagConstraints.BOTH;
buttonSend.setFont(new Font("Arial", Font.BOLD, 16));
add(buttonSend, constraints);
buttonSend.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
buttonSendActionPerformed(event);
}
});
constraints.gridx = 0;
constraints.gridy = 2;
constraints.gridheight = 1;
constraints.gridwidth = 3;
filePicker.setMode(JFilePicker.MODE_OPEN);
add(filePicker, constraints);
constraints.gridy = 3;
constraints.weightx = 1.0;
constraints.weighty = 1.0;
add(new JScrollPane(textAreaMessage), constraints);
}
private void buttonSendActionPerformed(ActionEvent event) {
if (!validateFields()) {

10. return;
}
String toAddress = fieldTo.getText();
String subject = fieldSubject.getText();
String message = textAreaMessage.getText();
File[] attachFiles = null;
if (!filePicker.getSelectedFilePath().equals("")) {
File selectedFile = new File(filePicker.getSelectedFilePath());
attachFiles = new File[] {selectedFile};
}
try {
Properties smtpProperties = configUtil.loadProperties();
EmailUtility.sendEmail(smtpProperties, toAddress, subject, message, attachFiles);
JOptionPane.showMessageDialog(this,
"The e-mail has been sent successfully!");
} catch (Exception ex) {
JOptionPane.showMessageDialog(this,
"Error while sending the e-mail: " + ex.getMessage(),
"Error", JOptionPane.ERROR_MESSAGE);
}
}
private boolean validateFields() {
if (fieldTo.getText().equals("")) {
JOptionPane.showMessageDialog(this,
"Please enter To address!",
"Error", JOptionPane.ERROR_MESSAGE);
fieldTo.requestFocus();
return false;
}

11. if (fieldSubject.getText().equals("")) {
JOptionPane.showMessageDialog(this,
"Please enter subject!",
"Error", JOptionPane.ERROR_MESSAGE);
fieldSubject.requestFocus();
return false;
}
if (textAreaMessage.getText().equals("")) {
JOptionPane.showMessageDialog(this,
"Please enter message!",
"Error", JOptionPane.ERROR_MESSAGE);
textAreaMessage.requestFocus();
return false;
}
return true;
}
public static void main(String[] args) {
// set look and feel to system dependent
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
ex.printStackTrace();
}
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new SwingEmailSender().setVisible(true);
}
});
}
}