Java Mail POST Message Body

Question

I'm trying to read in emails, save the email as an object, save their attachments and then POST the object as JSON to an API. Everything works fine except that the body only outputs as com.sun.mail.util.BASE64DecoderStream@1q9q9qj4. I thought the code would handle the message body with attachments but it doesn't seem to work.

public class ReadEmails {
    private static String saveDirectory = "C://attachments"; 

    public void setSaveDirectory(String dir) {
        ReadEmails.saveDirectory = dir;
    }

    public static void downloadEmailAttachments(String host, String port, String userName, String password) {
        Properties properties = new Properties();

        properties.put("mail.pop3.host", host);
        properties.put("mail.pop3.port", port);
        properties.put("mail.pop3.starttls.enable", "true");
        properties.put("mail.pop3.ssl.trust", host);
        properties.setProperty("mail.pop3.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
        properties.setProperty("mail.pop3.socketFactory.fallback", "true");
        properties.setProperty("mail.pop3.socketFactory.port", String.valueOf(port));

        Session session = Session.getDefaultInstance(properties);

        try {
            Store store = session.getStore("pop3");
            store.connect(userName, password);

            Folder folderInbox = store.getFolder("INBOX");
            folderInbox.open(Folder.READ_ONLY);

            Message[] arrayMessages = folderInbox.getMessages();

            for (int i = 0; i < arrayMessages.length; i++) {
                Message message = arrayMessages[i];
                Address[] fromAddress = message.getFrom();
                String from = fromAddress[0].toString();
                String subject = message.getSubject();
                String sentDate = message.getSentDate().toString();

                String contentType = message.getContentType();
                String messageContent = "";

                String attachFiles = "";

                if (contentType.contains("multipart")) {
                    // content may contain attachments
                    Multipart multiPart = (Multipart) message.getContent();
                    int numberOfParts = multiPart.getCount();
                    for (int partCount = 0; partCount < numberOfParts; partCount++) {
                        MimeBodyPart part = (MimeBodyPart) multiPart.getBodyPart(partCount);
                        if (Part.ATTACHMENT.equalsIgnoreCase(part.getDisposition())) {
                            // this part is attachment
                            String fileName = part.getFileName();
                            attachFiles += fileName + ", ";
                            part.saveFile(saveDirectory + File.separator + fileName);
                        } else {
                            // this part may be the message content
                            messageContent = part.getContent().toString();
                        }
                    }

                    if (attachFiles.length() > 1) {
                        attachFiles = attachFiles.substring(0, attachFiles.length() - 2);
                    }
                } else if (contentType.contains("text/plain") || contentType.contains("text/html")) {
                    Object content = message.getContent();
                    if (content != null) {
                        messageContent = content.toString();
                    }
                }


                NewCase nc = new NewCase();
                nc.setTitle(subject);
                nc.setDescription(messageContent);
                nc.setEmail(from);

                sendEmails(nc);
                System.out.print("email: "+ nc.getTitle() + nc.getDescription() + nc.getEmail());
            }

            folderInbox.close(false);
            store.close();
        } catch (NoSuchProviderException ex) {
            System.out.println("No provider for pop3.");
            ex.printStackTrace();
            System.out.println(ex);;
        } catch (MessagingException ex) {
            System.out.println("Could not connect to the message store");
            ex.printStackTrace();
            System.out.println(ex);;
        } catch (IOException ex) {
            ex.printStackTrace();
            System.out.println(ex);;
        }
    }
    static void sendEmails(NewCase nc) {
        final String url = "http://localhost:8080/email";

        String title = nc.getTitle();
        String description = nc.getDescription();
        String email = nc.getEmail();

        HttpClient httpClient = HttpClientBuilder.create().build();     
            HttpPost p = new HttpPost(url);        

            p.setEntity(new StringEntity("{\"title\":\"" + title + "\",\"description\":\"" + description + "\",\"email\":\""+ email +"\"}", 
                             ContentType.create("application/json")));

            try {
                HttpResponse r = httpClient.execute(p);
                System.out.println(r.getStatusLine().getStatusCode());

            } catch (ClientProtocolException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
}