.MessagingException - Missing start boundary when loading a mail twice

Question

Hi!
I have found a very interesting behaviour. When parsing a multipart mail twice, there is an error "javax.mail.MessagingException: Missing start boundary". This happens for every multipart mail which is fetched via POP3 and seems to be independant of both POP3 Server and the mail client the message was built with.
Environment:
debian linux, amd64, java 1.6
latest javamail from https://hg.kenai.com/hg/javamail~mercurial
Test program:
import java.io.*;
import javax.mail.*;
public class Mailtest {
     private final static void loadMail(Part p) throws Exception{
          Object content = p.getContent();
          if (content instanceof Multipart) {
               Multipart mp = (Multipart) content;
               int cnt = mp.getCount();
               for (int u=0;u<cnt;u++) {
                    loadMail(mp.getBodyPart(u));
     public final static void main(String[] args) throws Exception {
          //System.setProperty("mail.mime.cachemultipart", "true");
          java.util.Properties props = new java.util.Properties();
          Session mailSession = Session.getInstance(props, null);
          Store store = mailSession.getStore("pop3");
          store.connect("pop3srv", 110, "username", "pwd");
          Folder folder = store.getFolder("INBOX");
          folder.open(Folder.READ_WRITE);
          Message[] msgs = folder.getMessages();
          for (int i=0;i<msgs.length;i++) {
               /*if (msgs[i] instanceof com.sun.mail.pop3.POP3Message) {
                    System.out.println("inputstream");
                    InputStream in = msgs.getDataHandler().getInputStream();
                    in.close();
               System.out.println("i=" + i + " try = 1");
               loadMail(msgs[i]);
               System.out.println("i=" + i + " try = 2");
               loadMail(msgs[i]);     
Output:
i=0 try = 1
i=0 try = 2
Exception in thread "main" javax.mail.MessagingException: Missing start boundary
at javax.mail.internet.MimeMultipart.parsebm(MimeMultipart.java:882)
at javax.mail.internet.MimeMultipart.parse(MimeMultipart.java:503)
at javax.mail.internet.MimeMultipart.getCount(MimeMultipart.java:244)
at testapp.Mailtest.loadMail(Mailtest.java:11)
at testapp.Mailtest.main(Mailtest.java:38)
Java Result: 1
I thought that the 2 code blocks which are commented might be a workaround, but nothing changed if both blocks are active.
BTW: What is "mail.mime.multipart.bmparse" supposed to do?

Answer 1

Yes, thank you, that's a bug introduced in the (not yet final) JavaMail 1.4.4 release.
I've fixed it. I'll push the fix soon.
mail.mime.multipart.bmparse is a property to control whether the old (slow) multipart parser
is used, or the new (fast) Boyer-Moore multipart parser is used.