Reading Email Attachments Using JavaMail - Reading 'winmail.dat' Rather Than Actual Attachment

Question

I am attempting to build a client that uses the javax.mail API to read email messages, including attachments. My initial thought was to use the Tika library. When that produced an unexpected result (please refer to code and details below), I tried using a variation of the code presented in this question .

My function for reading emails:

    // Reference: https://www.tutorialspoint.com/javamail_api/javamail_api_checking_emails.htm
public class CheckingMails {

    public static void check(String host, String storeType, String user, String password) {
        try {

            // create properties field
            Properties properties = new Properties();

            properties.put("mail.pop3.host", host);
            properties.put("mail.pop3.port", "110");
            Session emailSession = Session.getInstance(properties);
            Store store = emailSession.getStore("pop3");
            store.connect(host, user, password);
            Folder emailFolder = store.getFolder("INBOX");
            emailFolder.open(Folder.READ_WRITE);

            // retrieve the messages from the folder in an array and print it
            Message[] messages = emailFolder.getMessages();

            System.out.println("messages.length---" + messages.length);

            for (int i = 0, n = messages.length; i < n; i++) {
                Message message = messages[i];

                Object content = message.getContent();
                if (content instanceof java.lang.String) {
                    System.out.println((String) content);
                } else if (content instanceof Multipart) {
                    Multipart mp = (Multipart) content;

                    for (int j = 0; j < mp.getCount(); j++) {
                        Part part = mp.getBodyPart(j);

                        String disposition = part.getDisposition();

                        if (disposition == null) {
                            // Check if plain
                            MimeBodyPart mbp = (MimeBodyPart) part;
                            if (mbp.isMimeType("text/plain")) {
                                System.out.println("Mime type is plain");
                                System.out.println((String) mbp.getContent());
                            } else {

                                // Special non-attachment cases here of
                                // image/gif, text/html, ...

                                System.out.println("File name is " + part.getFileName());

                            }
                        } else if ((disposition != null)
                                && (disposition.equals(Part.ATTACHMENT) || disposition.equals(Part.INLINE))) {
                            // Check if plain
                            MimeBodyPart mbp = (MimeBodyPart) part;
                            if (mbp.isMimeType("text/plain")) {
                                System.out.println("Mime type is plain");
                                System.out.println((String) mbp.getContent());
                            } else {
                                System.out.println("Save file " + part.getFileName());

                            }
                        }
                    }
                }

                System.out.println("Tika results " + parseMsg(message));

            }

            // close the store and folder objects
            emailFolder.close(false);
            store.close();

        } catch (MessagingException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

When I test the program by sending a test message with a simple CSV as an attachment, the Tika parser outputs the following (truncated for brevity):

    ------=_NextPart_000_0028_01D47C16.81FB45C0
    Content-Type: application/ms-tnef;
        name="winmail.dat"
    Content-Transfer-Encoding: base64
    Content-Disposition: attachment;
        filename="winmail.dat"

    eJ8+IhUSAQaQCAAEAAAAAAABAAEAAQeQBgAIAAAA5AQAAAAAAADoAAEIgAcAGAAAAElQTS5NaWNy
    b3NvZnQgTWFpbC5Ob3RlADEIAQOQBgCgDQAANgAAAAsAAgABAAAAAwAmAAAAAAALACkAAAAAAB4A
    cAABAAAABQAAAFRlc3QAAAAAAgFxAAEAAAAWAAAAAdR8SMswwghurPF+SpeO8uRrTzrhCgAACwAB
    DgAAAAACAQoOAQAAABg..... 

------=_NextPart_000_0028_01D47C16.81FB45C0--

The other portion of the code (that checks for the message's disposition), outputs something similar to the following:

 messages.length---1
Mime type is plain



Email Boday



Save file winmail.dat

Why is the application reading/recognizing winmail.dat and not the attachment that was actually sent with the message (a CSV file)?

Thanks for any help.