code: private static void byte2hex(byte b, StringBuffer buf) {
          char[] hexChars = { '0', '1', '2', '3', '4', '5', '6', '7', '8',
                  '9', 'A', 'B', 'C', 'D', 'E', 'F' };
          int high = ((b & 0xf0) >> 4);
          int low = (b & 0x0f);
          buf.append(hexChars[high]);
          buf.append(hexChars[low]);
      }
docs: Converts a byte to hex digit and writes to the supplied buffer