Java tutorial
//package com.java2s; public class Main { private static byte[] hexStringToByteArray(final String s) { final int len = s.length(); final byte[] data = new byte[len / 2]; for (int i = 0; i < len; i += 2) { data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character.digit(s.charAt(i + 1), 16)); } return data; } }