How can I read a message with Content-transfer-encoding header 8 bit using JavaMail 1.1.3?

According to the API Specification, 8bit is supported, because its part of the RFC2045 specification.
The MimeUtility.decode(java.io.InputStream is, java.lang.String encoding) method should help you to "read" parts of the message.
The following code might help or at least give an idea:

//assume you have a MimeBodyPart mbp
  InputStream in=mbp.getInputStream();
  String[] encoding=mbp.getHeader("Content-Transfer-Encoding");
  if(encoding!=null && encoding.length>0){ 
    in=MimeUtility.decode(in,encoding[0]);
  }

//use the Stream in to read from...