code: private static String convertJava2MimeEncoding(String encoding)
      {
          EncodingInfo enc =
              (EncodingInfo) _encodingTableKeyJava.get(toUpperCaseFast(encoding));
          if (null != enc)
              return enc.name;
          return encoding;
      }
docs: Try the best we can to convert a Java encoding to a XML-style encoding.
  <p>
  This is not a public API.
  @param encoding non-null reference to encoding string, java style.
  
  @return ISO-style encoding string.
  @xsl.usage internal