code: @Deprecated
      public static byte[] fromHexString(String hexString, int offset, int length) {
          return HexUtil.toByteArray(hexString, offset, length);
      }
docs: Convert a hexidecimal string generated by toHexString() back into a byte array.
  @param s String to convert
  @param offset starting character (zero based) to convert.
  @param length number of characters to convert.
  @return the converted byte array. Returns null if the length is not a multiple of 2.
  @deprecated Please use new utility class HexUtil
  @see HexUtil#toByteArray(java.lang.CharSequence, int, int)