Correct way to copy Multipart and prevent Missing start boundary Exception

Question

Hi there
I've worked through the FAQ's and forum and based on the info available tried to construct code to deal with the whole "javax.mail.MessagingException: Missing start boundary" problem. I keep on getting a ClassCastException though and was hoping you could scan through the code and let me know if you see anything. I must be missing something ... simplified extract of code below:
Multipart mp = (Multipart)part.getContent();
try {
     for (int i = 0; i < mp.getCount(); i++) {
          processBodyPart(wrapper, mp.getBodyPart(i), i);
} catch (MessagingException e) {
     // Converting Msg to a Copy (to fix boundary)
     ByteArrayOutputStream bos = new ByteArrayOutputStream();
     part.writeTo(bos);
     byte[] bytes = bos.toByteArray();
     MimeMessage newMsg = new MimeMessage(emailAccount.getSession(), new ByteArrayInputStream(bytes));
     String ct = newMsg.getContentType();
     newMsg.removeHeader("Content-Type");
     ct = ct.substring(0, ct.indexOf(";")); // Strip out the rest, only retain the content-type
     newMsg.setDataHandler(new DataHandler(newMsg.getContent(), ct));
     Multipart testMp = (Multipart)newMsg.getContent(); // <<-------- ClassCastException here!!
     for (int i = 0; i < testMp.getCount(); i++) {
          Part bp = testMp.getBodyPart(i);
          processBodyPart(bp);
}Much appreciated.
Marius

Answer 1

I took out the truncating part to make the example shorter,
but I did try both keeping it as it was, as well as truncating
it (it is "multipart/mixed") with the same effect.
I was able to save the entire message to file (thanks), attached
below - maybe you can spot something that could be causing it?
Thanks again.
X-Original-To: [email protected]
Delivered-To: [email protected]
Received: from mail.adept.co.za (localhost [127.0.0.1])
     by mail.adept.co.za (Postfix) with ESMTP id E3074C03D9
     for <[email protected]>; Fri, 18 Jan 2008 14:35:29 +0200 (SAST)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.4
Received: from mail-03.jhb.wbs.co.za (mail-03.jhb.wbs.co.za [196.2.97.2])
     by mail.adept.co.za (Postfix) with ESMTP id CA3AEC03D7
     for <[email protected]>; Fri, 18 Jan 2008 14:35:28 +0200 (SAST)
Received: from localhost by mail-03.jhb.wbs.co.za;
  18 Jan 2008 14:35:28 +0200
Date: 18 Jan 2008 14:35:28 +0200
To: [email protected]
From: "Mail Delivery System" <[email protected]>
Subject: Delivery Status Notification (Failure)
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status; boundary="9sdJO.4G/vWebcc.bcm9J.Ak/cwPA"
Message-Id: <[email protected]>
X-Virus-Scanned: ClamAV Passed
X-Spam-Scanned: -1.4
X-Scanned-By: proxfilter
--9sdJO.4G/vWebcc.bcm9J.Ak/cwPA
content-type: text/plain;
    charset="utf-8"
Content-Transfer-Encoding: quoted-printable
The following message to <[email protected]> was undeliverable.
The reason for the problem:
5.1.2 - Bad destination host 'DNS Hard Error looking up onyxit.co.za (MX): =
NXDomain'
--9sdJO.4G/vWebcc.bcm9J.Ak/cwPA
content-type: message/delivery-status
Reporting-MTA: dns; jnb-mailfw01.wbs.co.za
Final-Recipient: rfc822;[email protected]
Action: failed
Status: 5.0.0 (permanent failure)
Diagnostic-Code: smtp; 5.1.2 - Bad destination host 'DNS Hard Error looking up onyxit.co.za (MX):  NXDomain' (delivery attempts: 0)
--9sdJO.4G/vWebcc.bcm9J.Ak/cwPA
content-type: message/rfc822
Received: from wbs-smtp-out-02.jhb.wbs.co.za (HELO wbs-smtp-out-02) ([196.2.97.197])
  by mail-03.jhb.wbs.co.za with ESMTP; 18 Jan 2008 14:35:28 +0200
Received: from wbs-smtp-out-02.jhb.wbs.co.za (HELO wbs-smtp-out-02) ([196.2.97.197])
  by mail-03.jhb.wbs.co.za with ESMTP; 18 Jan 2008 14:35:28 +0200
Received: from wbs-41-208-227-16.wbs.co.za ([41.208.227.16] helo=jnfsworkpool)
     by wbs-smtp-out-02 with esmtp (Exim 4.67)
     (envelope-from <[email protected]>)
     id 1JFqSK-0000qy-8m; Fri, 18 Jan 2008 14:36:30 +0200
Date: Fri, 18 Jan 2008 14:35:10 +0200 (SAST)
From: Ros Copeling <[email protected]>
To: [email protected]
Cc: [email protected]
Message-ID: <[email protected]>
Subject: FW: Fw: Message from ESKOM
MIME-Version: 1.0
Content-Type: multipart/mixed;
     boundary="----=_Part_16_32195616.1200659710788"
X-Priority: 3
Importance: normal
Sensitivity: Normal
workpool_message_id: 6879
X-Original-Subject: FW: Fw: Message from ESKOM
X-Spam-Ignored: [TOO LARGE] Message > 100K
X-Scan-Signature: 66244f1a8ccb48c519852bcb33c1a261
--9sdJO.4G/vWebcc.bcm9J.Ak/cwPA--