How to use JavaMail to send email via an SMTP server. I was recently working with a server component that allowed for scheduling reports, which included email notification. I wanted to isolate the email notification portion. Check. :)

Java-Mail.md

JavaMail

SMTP test driver using JavaMail version 1.5.2.

# SSL/TLS port: 465
# Otherwise: 587
smtp.host=smtp.mail.yahoo.com
smtp.port=465
smtp.useSsl=true
 
# Change these...
smtp.user=user@yahoo.com
smtp.from=legit_user@yahoo.com
smtp.to=user@gmail.com,user2@gmail.com
smtp.subject=Java Mail Test Subject
smtp.text=This is a test message sent from a Java test driver. Please enjoy!

JavaMail FAQ - Gmail Example

SSH Port Forwarding

Using PuTTy (or SSH) you can set up an SSH tunnel and port forward out! I used PuTTy to tunnel through my local port 8085.

For command line SSH, try ssh -L 8085:smtp.mail.yahoo.com:465 -i priv_key.pem [email protected]

haysg@HOUHAYSG04 ~
$ ssh -L 8086:smtp.mail.yahoo.com:465 [email protected] -i /cygdrive/c/Users/haysg/Dropbox/Minecraft/River.pem
Last login: Thu Jul  3 17:41:12 2014 from test-8.qtip.org

       __|  __|_  )
       _|  (     /   Amazon Linux AMI
      ___|\___|___|

https://aws.amazon.com/amazon-linux-ami/2013.09-release-notes/
31 package(s) needed for security, out of 159 available
Run "sudo yum update" to apply all updates.
Amazon Linux version 2014.03 is available.
[ec2-user@ip-10-64-41-194 ~]$

Troubleshooting

Be sure to prefix with username, e.g. ec2-user@

haysg@HOUHAYSG04 ~
$ ssh -L 8086:smtp.mail.yahoo.com:465 54.197.110.138 -i /cygdrive/c/Users/haysg/Dropbox/Minecraft/River.pem
Permission denied (publickey). <--- It will fail

MailTestMain.java

package org.gkh.mail;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Message.RecipientType;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

/**
 * A handy SMTP test driver using JavaMail. Uses version 1.5.2 of JavaMail.
 * @see <a href="https://java.net/projects/javamail/pages/Home">JavaMail</a>
 * <p>
 * This class works with a property file that is expected in the test subfolder, 
 * e.g. test/test.properties. It should be of the form:
 * <p>
 * # SSL/TLS port: 465
 * # Otherwise: 587
 * smtp.host=smtp.mail.yahoo.com
 * smtp.port=465
 * smtp.useSsl=true
 *
 * # Change these...
 * [email protected]
 * [email protected]
 * [email protected],[email protected]
 * smtp.subject=Java Mail Test Subject
 * smtp.text=This is a test message sent from a Java test driver. Please enjoy!
 * <p>
 * The following code sample is taken from the Gmail example from the JavaMail FAQ.
 * @see <a href="http://www.oracle.com/technetwork/java/javamail/faq/index.html#gmail">Gmail Example</a>
 * <p>
 * {@code
 * String host = "smtp.gmail.com";
 * Properties prop = loadProperties();
 * 
 * final String user = prop.getProperty("smtp.user");
 * final String password = prop.getProperty("smtp.pass");
 * Properties smtpProps = new Properties();
 * Session session = Session.getInstance(smtpProps);
 * Transport t = session.getTransport("smtps");
 * 
 * try {
 *     t.connect(host, user, password);
 *     t.sendMessage(msg, msg.getAllRecipients());
 * } finally {
 *     t.close();
 * }
 * }
 * 		
 * @author gkhays
 */
public class MailTestMain {
	
	public enum SmtpTransport {
		SMTP,
		SMTPS
	}
	
	public static Properties getSmtpProperties(String host, String port,
			boolean useSmtpAuth, boolean useSsl) {
		Properties props = new Properties();
		props.put("mail.smtp.port", port);
		props.put("mail.smtp.host", host);
		props.put("mail.smtp.debug", "true");
		if (useSmtpAuth) {
			props.put("mail.smtp.auth", "true");			
		}
		if (useSsl) {
			props.put("mail.smtp.ssl.enable", "true");
			props.put("mail.smtp.starttls.enable", "true");
		}
		return props;
	}

	public static Properties getTlsSmtpProperties(String host, String port,
			boolean useSmtpAuth, boolean useSsl) {
		Properties tlsProps = new Properties();
		
		// If you intend to use SSL/TLS, you will want to set the transport to 
		// "smtps" and use the mail.smtps.xxx properties.
		tlsProps.put("mail.smtps.port", port);
		tlsProps.put("mail.smtps.host", host);
		tlsProps.put("mail.smtps.debug", "true");
		if (useSmtpAuth) {
			tlsProps.put("mail.smtps.auth", "true");
		}
		if (useSsl) {
			tlsProps.put("mail.smtps.ssl.enable", "true");
			tlsProps.put("mail.smtps.starttls.enable", "true");
		}
		return tlsProps;
	}

	public static Properties loadProperties() throws Exception {
		Properties prop = new Properties();
		prop.load(new FileInputStream("test/test.properties"));
		return prop;
	}
	
	/**
	 * Send a message over the given session.
	 * 
	 * @param	session	a session object that can be used to connect to an SMTP server
	 * @param	props	the properties contains SMTP information
	 * @param	msg		the MIME message contents
	 * @see		Session
	 * @see		Properties
	 * @see		MimeMessage
	 */
	public static void send(Session session, Properties props, MimeMessage msg,
			SmtpTransport st, boolean useSmtpAuth) throws Exception {
		String host = props.getProperty("smtp.host");
		Transport transport;
		if (st.equals(SmtpTransport.SMTPS)) {
			transport = session.getTransport("smtps");
			System.out.println("Using smtps transport");
		} else {
			transport = session.getTransport("smtp");
			System.out.println("Using smtp transport");
		}

		final String user = props.getProperty("smtp.user");
		final String password = props.getProperty("smtp.pass");
		if (password == null) {
			System.out.println("We didn't get a password!");
		}
		
		try {
			if (useSmtpAuth) {
				System.out.println("Connecting to " + host + " as " + user);
				transport.connect(host, user, password);
			} else {
				transport.connect();
			}
			transport.sendMessage(msg, msg.getAllRecipients());
			System.out.println("Message sent");
		} finally {
			transport.close();
			System.out.println("Connection to " + host + " closed");
		}
	}

	// Links:
	// http://www.oracle.com/technetwork/java/javamail/faq/index.html#gmail
	// http://www.oracle.com/technetwork/java/javamail/faq/index.html#commonmistakes
	// http://www.mkyong.com/java/javamail-api-sending-email-via-gmail-smtp-example/
	// http://www.rgagnon.com/javadetails/java-0538.html
	// https://blogs.oracle.com/apanicker/entry/java_code_for_smtp_server
	// http://stackoverflow.com/questions/19115732/send-mail-in-javax-mail-without-authentication
	// http://stackoverflow.com/questions/10409517/trouble-sending-via-gmails-smtp-server-with-java
	
	// Additional settings.
	//props.put("mail.smtp.userset", true); // use RSET instead of NOOP
	//props.put("mail.smtp.connectiontimeout", 60000);
	//props.put("mail.smtp.timeout", 60000);
	
	// Typical SSL/TLS and non-SSL ports:
	// Yahoo! Mail SMTP port: 465
	// Yahoo! Mail SMTP TLS/SSL required: yes
	// "mail.smtp.port", "587"

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws Exception {
		Properties prop = loadProperties();
		
		// If password is supplied, set useSmtpAuth to true.
		boolean useSmtpAuth = false;
		String pass = null;
		if (args[0] != null) {
			pass = args[0];
			useSmtpAuth = true;
			prop.setProperty("smtp.pass", pass);
		}
		
		String port = prop.getProperty("smtp.port", "25");
		String host = prop.getProperty("smtp.host", "netiqmta.netiq.com");
		
		Properties smtpProps;
		boolean useSsl = Boolean.parseBoolean(prop.getProperty("smtp.useSsl",
				"false"));
		if (useSsl) {
			smtpProps = getTlsSmtpProperties(host, port, useSmtpAuth, useSsl);
		} else {
			smtpProps = getSmtpProperties(host, port, useSmtpAuth, useSsl);
		}

		/*
		 * How you might get an authenticated session.
		 * {@code
		 * if (useSmtpAuth) {
		 *     session = getAuthenticatedSession(prop, pass);
		 * }
		 * }
		 */
		Session session;
		session = Session.getInstance(smtpProps);
		session.setDebug(true);
		debugSession(session);

		String text = prop.getProperty("smtp.text", "Ping!");
		MimeMessage msg = getMessage(text, session);
		SmtpTransport st;
		if (useSsl) {
			st = SmtpTransport.SMTPS;
		} else {
			st = SmtpTransport.SMTP;
		}
		send(session, prop, msg, st, useSmtpAuth);
	}

	private static void debugSession(Session session) {
		Properties sessionProps = session.getProperties();
		sessionProps.list(System.out);
	}

	/**
	 * Using an authenticator is still supported, but is no longer necessary.
	 * Just use the overloaded Transport.connect() method instead.
	 * 
	 * @see <a href="http://www.oracle.com/technetwork/java/javamail/faq/index.html#commonmistakes">JavaMail Common Mistakes</a>
	 */
	@SuppressWarnings("unused")
	@Deprecated
	private static Session getAuthenticatedSession(Properties smtpProps,
			String pass) throws Exception {
		Properties prop = loadProperties();
		final String username = prop.getProperty("smtp.user");
		final String password = pass;

		System.out.println("Using session authenticator with user: " + username);
		Authenticator auth = new Authenticator() {
			protected PasswordAuthentication getPasswordAuthentication() {
				return new PasswordAuthentication(username, password);
			}
		};
		return Session.getInstance(smtpProps, auth);
	}
	
	/**
	 * Prepare a MIME message to send via SMTP.
	 * 
	 * @param text
	 * @param fromEmail
	 * @param recipientList
	 * @param session
	 * @return
	 * @throws Exception 
	 */
	private static MimeMessage getMessage(String text, Session session)
			throws Exception {
		MimeMessage msg = new MimeMessage(session);

		Properties prop = loadProperties();
		String subject = prop.getProperty("smtp.subject", "Test subject");
		String fromEmail = prop.getProperty("smtp.from");
		String recipients = prop.getProperty("smtp.to");
		List<String> recipientList;
		recipientList = Arrays.asList(recipients.split(","));
		for (String to : recipientList) {
			msg.addRecipients(RecipientType.TO, to);
		}

		msg.setFrom(new InternetAddress(fromEmail, false));
		msg.setSubject(subject, "UTF-8");

		MimeMultipart mp = new MimeMultipart();
		MimeBodyPart partText = new MimeBodyPart();
		partText.setText(text);
		mp.addBodyPart(partText);
		msg.setContent(mp);
		return msg;
	}
}

results.txt

DEBUG: setDebug: JavaMail version 1.5.2
-- listing properties --
mail.smtps.ssl.enable=true
mail.smtps.port=465
mail.smtps.starttls.enable=true
mail.smtps.host=smtp.mail.yahoo.com
mail.smtps.debug=true
mail.smtps.auth=true
DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtps,com.sun.mail.smtp.SMTPSSLTransport,Oracle]
Using smtps transport
Connecting to smtp.mail.yahoo.com as [email protected]
DEBUG SMTP: useEhlo true, useAuth true
DEBUG SMTP: trying to connect to host "smtp.mail.yahoo.com", port 465, isSSL true
220 smtp.mail.yahoo.com ESMTP ready
DEBUG SMTP: connected to host "smtp.mail.yahoo.com", port: 465

EHLO SOURCE.x.y.com
250-smtp.mail.yahoo.com
250-PIPELINING
250-SIZE 41697280
250-8 BITMIME
250 AUTH PLAIN LOGIN XYMCOOKIE
DEBUG SMTP: Found extension "PIPELINING", arg ""
DEBUG SMTP: Found extension "SIZE", arg "41697280"
DEBUG SMTP: Found extension "8", arg "BITMIME"
DEBUG SMTP: Found extension "AUTH", arg "PLAIN LOGIN XYMCOOKIE"
DEBUG SMTP: STARTTLS requested but already using SSL
DEBUG SMTP: Attempt to authenticate using mechanisms: LOGIN PLAIN DIGEST-MD5 NTLM 
DEBUG SMTP: AUTH LOGIN command trace suppressed
DEBUG SMTP: AUTH LOGIN succeeded
DEBUG SMTP: use8bit false
MAIL FROM:<[email protected]>
250 OK , completed
RCPT TO:<[email protected]>
250 OK , completed
RCPT TO:<[email protected]>
250 OK , completed
RCPT TO:<[email protected]>
250 OK , completed
DEBUG SMTP: Verified Addresses
DEBUG SMTP:   [email protected]
DEBUG SMTP:   [email protected]
DEBUG SMTP:   [email protected]
DATA
354 Start Mail. End with CRLF.CRLF
From: [email protected]
To: [email protected], [email protected], [email protected]
Message-ID: <7120662.1.1404420557774.JavaMail.gkhays@SOURCE>
Subject: Java Mail Test Subject
MIME-Version: 1.0
Content-Type: multipart/mixed; 
	boundary="----=_Part_0_27785692.1404420554739"

------=_Part_0_27785692.1404420554739
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

This is a test message sent from a Java test driver. Please enjoy!
------=_Part_0_27785692.1404420554739--
.
250 OK , completed
Message sent
QUIT
221 Service Closing transmission
Connection to localhost closed

SSH_Port_Forwarding.png

test.properties

# SSL/TLS port: 465
# Otherwise: 587
smtp.host=smtp.mail.yahoo.com
smtp.port=465
smtp.useSsl=true

# Change these...
[email protected]
[email protected]
[email protected],[email protected]
smtp.subject=Java Mail Test Subject
smtp.text=This is a test message sent from a Java test driver. Please enjoy!

replace the input check if no args given it will fail use:
args.length > 0
instead