title: JavaMail content-transfer-encoding issue
body: <p>I have some Java code which sends out an email with code somewhat like the following: Actually i got Mimemessage from Httprequest param and in that mimemessage i'm going to append some content to existing body.</p>
  
  <p>If Mimemessage is of Multipart content-type , i'm not facing any issue while sending message.</p>
  
  <p>If the message is of text/plain and text/html content-type, the content-transfer encoding which i set didn't applied to body.</p>
  
  <p>Based on this <a href="http://www.oracle.com/technetwork/java/faq-135477.html" rel="nofollow">docs</a></p>
  
  <p>Q: Even though JavaMail does all the encoding and decoding for me, I need to manually control the encoding for some body parts. A: In the rare case that you need to control the encoding, there are several ways to override JavaMail's default behavior. A simple approach is as follows. After creating the entire message, call msg.saveChanges() and then use something like mbp.setHeader("Content-Transfer-Encoding", "base64") to force base64 encoding for the given body part.</p>
  
  <p>Another approach is to subclass MimeBodyPart and override the updateHeaders method so that it first calls super.updateHeaders() and then sets the Content-Transfer-Encoding header as above.</p>
  
  <p>Applied above also. But it doesn't works for me.</p>
  
  <pre><code>InputStream ins = request.getInputStream();
  MimeMessage msg = new MimeMessage(session,ins);
  msg.setContent("some non-Ascii content","text/plain; charset="UTF-8"");
  //Tried setheader before saveChanges() method, also doesn't work for me
  //msg.setHeader("Content-Transfer-Encoding","base64"); 
  msg.saveChanges();
  //Now tried based on above docs after saveChanges method, also doesn't work
  msg.setHeader("Content-Transfer-Encoding","base64"); 
  </code></pre>
  
  <p>please help to solve this.</p>