JavaMail smtp properties (for STARTTLS)

Question

JavaMail specifies a bunch of properties that can be set to configure an SMTP connection. To use STARTTLS it is necessary to set the following property

mail.smtp.starttls.enable=true 

Where do I specify the username/password to use the smtp service? Is it enough to specify the:

mail.smtp.user=me mail.smtp.password=secret 

Or do I have to explicitely login using the:

transport.connect(server, userName, password) 

Yes, I already tried to do this and it seems that it is necessary to connect using transport.connect(..). But if yes, what are the mail.smtp.user & pass properties for? Are they not enough to use smtp with starttls?

Answer 1

Here is my sendEmail method which is using GMail smtp (JavaMail) with STARTTLS

public void sendEmail(String body, String subject, String recipient) throws MessagingException,             UnsupportedEncodingException {         Properties mailProps = new Properties();         mailProps.put("mail.smtp.from", from);         mailProps.put("mail.smtp.host", smtpHost);         mailProps.put("mail.smtp.port", port);         mailProps.put("mail.smtp.auth", true);         mailProps.put("mail.smtp.socketFactory.port", port);         mailProps.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");         mailProps.put("mail.smtp.socketFactory.fallback", "false");         mailProps.put("mail.smtp.starttls.enable", "true");          Session mailSession = Session.getDefaultInstance(mailProps, new Authenticator() {              @Override             protected PasswordAuthentication getPasswordAuthentication() {                 return new PasswordAuthentication(login, password);             }          });          MimeMessage message = new MimeMessage(mailSession);         message.setFrom(new InternetAddress(from));         String[] emails = { recipient };         InternetAddress dests[] = new InternetAddress[emails.length];         for (int i = 0; i < emails.length; i++) {             dests[i] = new InternetAddress(emails[i].trim().toLowerCase());         }         message.setRecipients(Message.RecipientType.TO, dests);         message.setSubject(subject, "UTF-8");         Multipart mp = new MimeMultipart();         MimeBodyPart mbp = new MimeBodyPart();         mbp.setContent(body, "text/html;charset=utf-8");         mp.addBodyPart(mbp);         message.setContent(mp);         message.setSentDate(new java.util.Date());          Transport.send(message);     }