question: public static byte [ ] asciiHexToBytes ( String hex ) throws DecoderException { return Hex . decodeHex ( hex . toCharArray ( ) ) ; }
target:  Convert a string of ASCII hex characters (e.g. "DEADBEEF0042") to an array of bytes the hex represents (e.g. [0xDE, 0xAD, 0xBE, 0xEF, 0x00, 0x42]). Treat bytes returned by this method as unsigned.