JavaMail invalid MSGID
===

I am running a JBoss server with underlaying Postfix server. When I am sending emails, JavaMail creates a invalid messageID, e.g. Message-ID: <47112553230.139.4972667128159.JavaMail.undefined>.

I am using this code for sending mails:

    Properties props = new Properties();
    props.put("mail.smtp.host", "xxx.tld");
    props.put("mail.host", "xxx.tld");
    InitialContext ictx = new InitialContext(props);
    Session sess = (Session) ictx.lookup("java:jboss/mail/Default");
    Transport trans = sess.getTransport("smtp");
    trans.connect();
    
    MimeMessage msg = new MimeMessage(sess);
    msg.setFrom(new InternetAddress(from));
    msg.addRecipients(RecipientType.TO, InternetAddress.parse(to, false));
    msg.setSubject(subject);
    msg.setText(message);
    msg.setHeader("Content-Type", "text/html; charset=\"utf-8\"");
    msg.saveChanges();
    
    Transport.send(msg, msg.getAllRecipients());
    trans.close();

The main postfix configuration:

    myhostname = xxx.tld
    alias_maps = hash:/etc/aliases
    alias_database = hash:/etc/aliases
    myorigin = /etc/mailname
    mydestination = xxx.tld, Debian-60-squeeze-64-minimal, localhost.localdomain, localhost
    relayhost = 
    mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
    mailbox_size_limit = 0
    recipient_delimiter = +
    inet_interfaces = 127.0.0.1

How can I fix this problem?

Best regards,
Christian