Attachment without multipart content type

Question

Hello,
My application receives mails sent from some different customers and parses the mail's attachments. The problem is that all these customers send their mails in a very different ways. Some of them send mails with "Content-Type: multipart/mixed;" header while some others send mail with the following headers (among some other):
MIME-Version: 1.0
Content-Type: application/xml
Date: Tue, 11 Feb 2014 18:33:26 +0000
From: <[email protected]>
Message-ID: <1392143606.220.1@cls0361>
Subject: orders000005311382.xml
To: <[email protected]>
There is no "Content-Type: multipart/mixed;" header at all. When I look at these messages with MS Outlook I can see that they have proper attachements.
Now I have 2 problems:
1. I would like to produce such an email myself since resending the received emails changes the message headers. There are lots of examples how to send a message with an attachment in Java with MimeMultipart object (this produces "Content-Type: multipart/mixed;") but I could not find one which sends the message with "Content-Type: application/xml" header only without any multipart header. I suspect that there are some specific applications which send mails in that way - not standard mail clients.
2. I would like to get the attachment of a received mail with "Content-Type: application/xml" header. The following code works for "Content-Type: multipart/mixed;" only:
public void invoke() throws Exception {
  /* Available Variables: DO NOT MODIFY
    In  : String mimeMessage
    In  : String encoding
    Out : String[] mimeParts
  * Available Variables: DO NOT MODIFY *****/
  javax.mail.util.ByteArrayDataSource ds = new javax.mail.util.ByteArrayDataSource(mimeMessage, "multipart/mixed");
  javax.mail.internet.MimeMultipart mm = new javax.mail.internet.MimeMultipart(ds);
  java.util.ArrayList<String> al = new java.util.ArrayList<String>();
  getAttachements(mm, al, 1);
  mimeParts = new String[0];
  mimeParts = al.toArray(mimeParts);
private void getAttachements(javax.mail.internet.MimeMultipart mm, ArrayList<String> al, int depth) throws Exception {
  if (depth > 9) {
    return;
  int mimePartsCount = mm.getCount();
  for (int i = 0; i < mimePartsCount; i++){
    javax.mail.internet.MimeBodyPart mbp = (javax.mail.internet.MimeBodyPart)mm.getBodyPart(i);
    //System.out.println(depth + ": " + mbp + " " + mbp.getContentType() + " " + mbp.getContentID() + " " + mbp.getDisposition());
    if(mbp.getContentType().startsWith("multipart")){
      javax.mail.util.ByteArrayDataSource ds2 = new javax.mail.util.ByteArrayDataSource(mbp.getInputStream(), "multipart/mixed");
      javax.mail.internet.MimeMultipart mm2 = new javax.mail.internet.MimeMultipart(ds2);
      getAttachements(mm2, al, depth+1);
    } else {
      if (mbp.getDisposition() != null && mbp.getDisposition().startsWith("attachment") && !mbp.getContentType().contains("signature")){
        BufferedReader br = new BufferedReader(new InputStreamReader(mbp.getInputStream(),encoding));
        String s = br.readLine();
        StringBuffer sb = new StringBuffer();
        while (s != null) {
          sb.append(s);
          s = br.readLine();
        al.add(sb.toString());
Could anyone suggest anything which may be helpful for resolving 1 or 2?
Best regards

Answer 1

You are right! parsing of such not-multipart mail may look like that:
if (contentType.startsWith("application/xml")) {
            //just a plain attachement which is a mail's content and not a multipart.
            mimeParts = new String[1];
            //according to RFC 2822 empty line separates headers from the body
            mimeParts[0] = mimeMessage.substring(mimeMessage.indexOf("\n\r")).trim();
} else {
            //multipart mail
            javax.mail.util.ByteArrayDataSource ds = new javax.mail.util.ByteArrayDataSource(mimeMessage, "multipart/mixed");
            javax.mail.internet.MimeMultipart mm = new javax.mail.internet.MimeMultipart(ds);
            java.util.ArrayList<String> al = new java.util.ArrayList<String>();
            getAttachements(mm, al, 1);
            mimeParts = new String[0];
            mimeParts = al.toArray(mimeParts);
Thanks!