String convertedString = new String(s.getBytes("UTF-8"), "UTF-8"); //is this correct, elegant etc?

//message is a String
//msg.setContent is this method http://docs.oracle.com/javaee/6/api/javax/mail/internet/MimeMessage.html#setContent%28java.lang.Object,%20java.lang.String%29

msg.setContent(message, "text/plain");
msg.addHeader("Content-Type", "text/plain; charset="utf-8"");