<property name="mail-smtps-starttls-enable" value="true"/>
    <property name="mail-smtps-socketFactory-port" value="465"/>
    <property name="mail-smtps-socketFactory-class" value="javax.net.ssl.SSLSocketFactory"/>
    <property name="mail-smtps-socketFactory-fallback" value="false"/>

    <mail-resource debug="true" enabled="true" from="${youruserid}@gmail.com" 
            host="smtp.gmail.com" jndi-name="mail/gmailSession" object-type="user" 
            store-protocol="imaps" store-protocol-class="com.sun.mail.imap.IMAPStore"
            transport-protocol="smtps" transport-protocol-class="com.sun.mail.smtp.SMTPTransport"
            user="${youruserid}">
        <description>GMail Mail Resource</description>
        <property name="mail-smtps-host" value="smtp.gmail.com"/>
        <property name="mail-smtps-port" value="465"/>
        <property name="mail-smtps-auth" value="true"/>
        <property name="mail-smtps-user" value="${youruserid}"/>
        <property name="mail-smtps-password" value="${yourpassword}"/>
        <property name="mail-smtps-starttls-enable" value="true"/>
        <property name="mail-smtps-socketFactory-port" value="465"/>
        <property name="mail-smtps-socketFactory-class" value="javax.net.ssl.SSLSocketFactory"/>
        <property name="mail-smtps-socketFactory-fallback" value="false"/>
    </mail-resource>
 
// Servlet code...
 
    @Resource(name = "mail/gmailSession")
    private Session mailSession;
 
    /** email = recipient@their_server
     *  subject, body = message text
     */
    void sendMail(String email, String subject, String body) throws MessagingException, NamingException {
        // username and password could come from anywhere, e.g. servlet session, etc.
        Properties props = mailSession.getProperties();
        String username = (String) props.get("mail.smtps.user");
        String password = (String) props.get("mail.smtps.password");
 
        MimeMessage message = new MimeMessage(mailSession);
        message.setSubject(subject);
        message.setRecipients(javax.mail.Message.RecipientType.TO, javax.mail.internet.InternetAddress.parse(email, false));
        message.setText(body);
        message.saveChanges();
 
        Transport transport = mailSession.getTransport("smtps");
        try {
            transport.connect(username, password);
            transport.sendMessage(message, message.getAllRecipients());
        } finally {
            transport.close();
        }
    }