How to Sign Javamail with DKIM

Question

Is there a library or a way to do this without an external library? I am using apache james as my mail server and currently send email like this:

public void sen         


        

Answer 1

Simple Java Mail recently added support for DKIM signing. Here's your code, but now with Simple Java Mail:

public void sendMessage(String to, String subject, String content) {
    final Email email = new Email.Builder()
            .from(null, from)
            .to(null, to)
            .subject(subject)
            .textHTML(content)
            .build();

    email.signWithDomainKey(new File(properties.getProperty("mail.smtp.dkim.privatekey")),
                            properties.getProperty("mail.smtp.dkim.signingdomain"),
                            properties.getProperty("mail.smtp.dkim.selector"));

    new Mailer(...).sendMail(email);
}

The private key argument can be a File, InputStream or a byte[].

Interestingly, Behind the scenes Simple Java Mail uses java-utils-mail-dkim (GitHub), which is an active fork on the dormant DKIM-for-JavaMail (GitHub), which was the continuation of the library you are using now, DKIM For Javamail (SourceForge). So, the one you are using is very old.