This is one of the examples in the javamail dev.kit.
      ///
      /// Send Message
      ///
      String to = args[0];
      String from = args[1];
      String host = args[2];
      boolean debug = Boolean.valueOf(args[3]).booleanValue();
   
      // create some properties and get the default Session
      Properties props = new Properties();
      props.put("mail.smtp.host", host);
   
      Session session = Session.getDefaultInstance(props, null);
      session.setDebug(debug);
      
      try {
          // create a message
          MimeMessage msg = new MimeMessage(session);
          msg.setFrom(new InternetAddress(from));
          InternetAddress[] address = {new InternetAddress(to)};
          msg.setRecipients(Message.RecipientType.TO, address);
          msg.setSubject("JavaMail APIs Multipart Test");
          msg.setSentDate(new Date());
   
          // create and fill the first message part
          MimeBodyPart mbp1 = new MimeBodyPart();
          mbp1.setText("Your mail");
   
          // create and fill the second message part
          MimeBodyPart mbp2 = new MimeBodyPart();
          // Use setText(text, charset), to show it off !
          mbp2.setContent(msgText2, "image/jpg");
   
          // create the Multipart and its parts to it
          Multipart mp = new MimeMultipart();
          mp.addBodyPart(mbp1);
          mp.addBodyPart(mbp2);
   
          // add the Multipart to the message
          msg.setContent(mp);
          
          // send the message
          Transport.send(msg);
      } catch (MessagingException mex) {
          mex.printStackTrace();
          Exception ex = null;
          if ((ex = mex.getNextException()) != null) {
         ex.printStackTrace();
          }
      }