Java tutorial
//package com.java2s; public class Main { public static String hexString2binaryString(String hexString) { if (hexString == null || hexString.length() % 2 != 0) return null; String bString = "", tmp; for (int i = 0; i < hexString.length(); i++) { tmp = "0000" + Integer.toBinaryString(Integer.parseInt(hexString.substring(i, i + 1), 16)); bString += tmp.substring(tmp.length() - 4); } return bString; } }