code: public String decodeHexToString(String str) throws DecoderException {
          String result = null;
          byte[] bytes = Hex.decodeHex(str.toCharArray());
          if (bytes != null && bytes.length > 0) {
              result = new String(bytes);
          }
          return result;
      }
docs: Decode the given hexidecimal formatted value into a string representing
  the bytes of the decoded value.
  
  @param str The hexidecimal formatted value
  
  @return The string representing the decoded bytes
  
  @throws DecoderException if an error occurs during decoding
  
  @see #decodeHex(String)