Here are the code extracted:

private void insertPart(Part p) throws MessagingException {
Multipart mp = null;
if (p.isMimeType("multipart/*")) {
mp = (Multipart) p.getContent();

.....

I am getting ClassCast exception in the p.getContent line, I stepped into the code and found that p.getContent return MimeMultipart, so it is okay to cast it to Mutlipart but I still getting ClassCaseException. Can somebody help?? Thanks!!