code: public static byte[] fromHexString(String s) {
  		if (s.length() % 2 != 0) {
  			throw new IllegalArgumentException(s);
  		}
  		byte[] array = new byte[s.length() / 2];
  		for (int i = 0; i < array.length; i++) {
  			int b = Integer.parseInt(s.substring(i * 2, i * 2 + 2), SIXTEEN);
  			array[i] = (byte) (_0XFF & b);
  		}
  		return array;
  	}
docs: /* ------------------------------------------------------------