private Session buildSession(MailConfig emailConfig) {
    Properties properties = new Properties();
    properties.setProperty("mail.smtp.host", emailConfig.getHost());
    properties.setProperty("mail.smtp.auth", "true");
    properties.setProperty("mail.smtp.port", String.valueOf(emailConfig.getPort()));

    //ssl
    properties.setProperty("mail.smtp.socketFactory.port", String.valueOf(emailConfig.getPort()));
    properties.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
    properties.setProperty("mail.smtp.socketFactory.fallback", "false");
    properties.setProperty("mail.smtp.starttls.enable", String.valueOf(true));
    properties.setProperty("mail.smtp.ssl.checkserveridentity", "true");

    //we only need to send the message so we use smtps
    properties.setProperty("mail.transport.protocol", "smtps");

    //explicit override stmp provider because of issues with relocation
    Session session = Session.getDefaultInstance(properties);
    try {
        session.setProvider(new Provider(Type.TRANSPORT, "smtps",
                "flexiblelogin.mail.smtp.SMTPSSLTransport", "Oracle", "1.6.0"));
    } catch (NoSuchProviderException noSuchProvider) {
        logger.error("Failed to add SMTP provider", noSuchProvider);
    }

    return session;
}
 

@Override
public MailSender createSender() throws Exception {
	MailSender mailSender = new MailSender() {
		Session mailSession;
		@Override
		protected Session createSession() throws SenderException {
			try {
				mailSession = super.createSession();
				Provider provider = new Provider(Type.TRANSPORT, "smtp", TransportMock.class.getCanonicalName(), "IbisSource.org", "1.0");
				mailSession.setProvider(provider);

				return mailSession;
			} catch(Exception e) {
				e.printStackTrace();
				throw new SenderException(e);
			}
		}

		@Override
		public Message sendMessage(Message message, IPipeLineSession session) throws SenderException, TimeOutException {
			super.sendMessage(message, session);
			session.put("mailSession", mailSession);
			String correlationID = session.getMessageId();
			return new Message(correlationID);
		}
	};
	mailSender.setSmtpHost("localhost");
	mailSender.setSmtpUserid("user123");
	mailSender.setSmtpPassword("secret321");
	return mailSender;
}