Someone knows a mail (SMTP) delivery library for Java?

Question

I'd like to send mail without bothering with the SMTP-Server which is used for delivery.

So JavaMail API doesn't work for me because I have to specify a SMTP server to connect to.

I'd like the library to find out on its own which SMTP server is responsible for which email address by querying the MX record of the mail address domain.

I'm looking for something like Aspirin. Unfortunately I can't use Aspirin itself because the development stopped 2004 and the library fails to communicate with modern spam hardened servers correctly.

An embeddable version of James would do the task. But I haven't found documentation concerning whether this is possible.

Or does anyone know about other libraries I could use?

Answer 1

One possible solution: get the MX record on your own and use JavaMail API.

You can get the MX record using the dnsjava project:

Maven2 dependency:

<dependency>
    <groupId>dnsjava</groupId>
    <artifactId>dnsjava</artifactId>
    <version>2.0.1</version>
</dependency>

Method for MX record retrieval:

public static String getMXRecordsForEmailAddress(String eMailAddress) {
    String returnValue = null;

    try {
        String hostName = getHostNameFromEmailAddress(eMailAddress);
        Record[] records = new Lookup(hostName, Type.MX).run();
        if (records == null) { throw new RuntimeException("No MX records found for domain " + hostName + "."); }

        if (log.isTraceEnabled()) {
            // log found entries for debugging purposes
            for (int i = 0; i < records.length; i++) {
                MXRecord mx = (MXRecord) records[i];
                String targetString = mx.getTarget().toString();
                log.trace("MX-Record for '" + hostName + "':" + targetString);
            }
        }

        // return first entry (not the best solution)
        if (records.length > 0) {
            MXRecord mx = (MXRecord) records[0];
            returnValue = mx.getTarget().toString();
        }
    } catch (TextParseException e) {
        throw new RuntimeException(e);
    }

    if (log.isTraceEnabled()) {
        log.trace("Using: " + returnValue);
    }
    return returnValue;
}

private static String getHostNameFromEmailAddress(String mailAddress) throws TextParseException {
    String parts[] = mailAddress.split("@");
    if (parts.length != 2) throw new TextParseException("Cannot parse E-Mail-Address: '" + mailAddress + "'");
    return parts[1];
}

Sending mail via JavaMail code:

public static void sendMail(String toAddress, String fromAddress, String subject, String body) throws AddressException, MessagingException {
    String smtpServer = getMXRecordsForEmailAddress(toAddress);

    // create session
    Properties props = new Properties();
    props.put("mail.smtp.host", smtpServer);
    Session session = Session.getDefaultInstance(props);

    // create message
    Message msg = new MimeMessage(session);
    msg.setFrom(new InternetAddress(fromAddress));
    msg.setRecipient(Message.RecipientType.TO, new InternetAddress(toAddress));
    msg.setSubject(subject);
    msg.setText(body);

    // send message
    Transport.send(msg);
}