title: How to control alignment of mail header?
body: <p>I encounter a situation, when I send a email which email subject more than 80 char, sometimes the email subject will be insert a 'tab' char. I check the invalid email's mail header, they are aligned, if a mail header entry more than 80 char, it will be wrap to a new line, and insert a 'tab'. I don't know which configuration control it, javaMail setting? SMTP setting? </p>
  
  <p>Sample headers:</p>
  
  <p>case one: invaild email subject, inserted a char 'tab'. </p>
  
  <pre><code>Received: from as09.aaaaaaaaa.com ([192.168.1.129]) by aaaaaaaaa.com
      ([192.168.1.49]) with ESMTP (TREND IMSS SMTP Service 7.0; TLS:
      TLSv1/SSLv3,168bits,DES-CBC3-SHA) id ba8afe04001a23ba ; Wed, 1 Feb 2012
      16:17:10 +0800
  Received: from as09 (localhost [127.0.0.1])by as09.aaaaaaaaa.com
      (8.13.8+Sun/8.13.8) with ESMTP id q118HAgi021891;Wed, 1 Feb 2012 16:17:10
      +0800 (HKT)
  Message-ID: &lt;25866052.1328084230581.JavaMail.oracle@as09&gt;
  Date: Wed, 1 Feb 2012 08:17:10 +0000
  From: &lt;sss@abc.com&gt;
  To: ben@abc.com,
      john@abc.com,
      jimmy@abc.com
  Subject: test Daily report for city pairs of iPhone App enquiries indocument
       version Demo Customer/Test/Test/123/1231
  CC: sam@abc.com
  MIME-Version: 1.0
  </code></pre>
  
  <p>case two: valid email subject, just wrapped</p>
  
  <pre><code>Received: from as08.aaaaaaaaa.com ([192.168.1.104]) by aaaaaaaaa.com
   ([192.168.1.49]) with ESMTP (TREND IMSS SMTP Service 7.0; TLS:
   TLSv1/SSLv3,168bits,DES-CBC3-SHA) id c356e969001b37a5 ; Fri, 3 Feb 2012
   09:16:58 +0800
  Received: from as08.aaaaaaaaa.com (localhost [127.0.0.1])   by
   as08.aaaaaaaaa.com (8.13.4+Sun/8.13.4) with ESMTP id q131Gw1l006160;   Fri, 3
   Feb 2012 09:16:58 +0800 (HKT)
  Message-ID: &lt;17351450.1328231818282.JavaMail.oracle@as08.aaaaaaaaa.com&gt;
  Date: Fri, 3 Feb 2012 01:16:58 +0000
  From: &lt;sss@abc.com&gt;
  To: ben@abc.com
  Subject: test Daily report for city pairs of iPhone App enquiries in
   document version Demo Customer/Test/Test/123/1231
  CC: sam@abc.com
  </code></pre>
  
  <p>sample java code:</p>
  
  <pre><code>public void sendEmail(Request req) throws Exception {
    Session mailSession;
    MimeMessage msg;
    Properties mailSessionProp = new Properties();
    mailSessionProp.put("mail.smtp.host", "localhost");
    mailSessionProp.put("mail.smtp.port", "25");
  
    mailSession = Session.getInstance(mailSessionProp, null);
    msg = new MimeMessage(mailSession);
    msg.addRecipients("TO", InternetAddress.parse(req.getRecipientAddress()));
    msg.setSubject(MimeUtility.encodeText(req.getSubject(), "UTF-8", "B"));
    msg.setHeader("X-Mailer", "");
    msg.setSentDate(new Date());
    msg.setContent(req.getMessage(), req.getMessageContentType().getType());
    Transport.send(msg);
  }
  </code></pre>
  
  <p>JavaMail:</p>
  
  <pre><code>    Manifest-Version: 1.0
      Implementation-Version: 1.3.3_01
      Specification-Title: JavaMail(TM) API Design Specification
      Specification-Version: 1.3
      Extension-Name: javax.mail
      Created-By: 1.3.1 (Sun Microsystems Inc.)
      Implementation-Vendor-Id: com.sun
      Implementation-Vendor: Sun Microsystems, Inc.
      Specification-Vendor: Sun Microsystems, Inc.
      SCCS-ID: @(#)javamail.mf    1.5 02/03/14
  </code></pre>