1. Get the count on MimeMultiPart which tells the total files uploaded. 2. Call getBodyPart(index i) . 3. BodyPart has the api's like getFileName(), getInputStream() which is the content of the part for ex. image file. 4. Now you have to create a file on the server and transfer this inputstream of the bodypart into the newly created file.
I wouldn't use the mail classes to upload the file... I'd use a separate set designed especially for uploads. Two that come to mind are the jakarta commons upload classes, and a set from O'Reily (think they're by Jason Hunter, the same person who wrote their servlet book).