public class Main {
    public static void main(String[] args){
        final String username = "labtime@mail.labtime.ufg.br";
        final String password = "Lt28xm37o1";

        Properties props = new Properties();
        props.put("mail.smtp.auth", true);
        props.put("mail.smtp.starttls.enable", true);
        props.put("mail.smtp.ssl.trust", "192.168.1.28");
        props.put("mail.smtp.host", "192.168.1.28");
        props.put("mail.smtp.port", "10587");

        Session session = Session.getInstance(props,
                new javax.mail.Authenticator() {
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(username, password);
                    }
                });

        try {

            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("labtime@mail.labtime.ufg.br"));
            message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse("rhandyrafhael@gmail.com"));
            message.setSubject("Dear Testing Subject");
            message.setText("Dear Mail Crawler,"
                    + "\n\n No spam to my email, please!");
            Transport.send(message);
            System.out.println("Done");

        } catch (MessagingException e) {
            throw new RuntimeException(e);
        }

    }
}