Sending mail using Gmail SMTP server with Java

This is a companion project of my previous experiment with S/Mime encryption. This script is also based on Beanshell and it's purpose is basically to connect to Gmail SMTP servers and deliver the encrypted payload to the message recipients.

There are several examples off the Internet but, somehow, I had to combine the techniques before I finally pulled this off. I've enabled debug, otherwise this post would not have any image at all!

Here's the debug output..


Here's the script..

addClassPath( "./mail.jar" );
addClassPath( "./activation.jar" );

import java.security.Security;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.Authenticator;
import javax.mail.internet.MimeMessage;

private class SMTPAuthenticator extends javax.mail.Authenticator {
 public PasswordAuthentication getPasswordAuthentication()
 {
 return new PasswordAuthentication(smtpUsername, smtpPassword);
 }
}

public static final String smtpHost = "smtp.gmail.com";
public static final String smtpUsername = "rexjun@gmail.com";
public static final String smtpPassword = "-change-me-";
public static final String smtpPort = "465";

Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());
Properties props = new Properties();
props.put("mail.smtp.user", smtpUsername);
props.put("mail.smtp.host", smtpHost);
props.put("mail.smtp.port", smtpPort);
props.put("mail.smtp.starttls.enable","true");
props.put("mail.smtps.auth", "true");
props.put("mail.smtp.debug", "true");
props.put("mail.smtp.socketFactory.port", smtpPort);
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.socketFactory.fallback", "false");
props.put("mail.smtp.ssl","true");

SecurityManager security = System.getSecurityManager();
Authenticator auth = new SMTPAuthenticator();
Session smtpSession = Session.getInstance(props, auth);
smtpSession.setDebug(true);

MimeMessage smtpMessage = new MimeMessage(smtpSession,
 new FileInputStream("Encrypted.eml"));
smtpMessage.saveChanges();
smtpMessage.setSentDate(new Date());

Transport tr = smtpSession.getTransport("smtp");   
tr.connect(smtpHost, smtpUsername, smtpPassword);
tr.sendMessage(smtpMessage, smtpMessage.getAllRecipients());
tr.close();