Java tutorial
//package com.java2s; public class Main { private static String toHex(byte[] buf) { if (buf == null) { return ""; } StringBuffer result = new StringBuffer(2 * buf.length); for (byte aBuf : buf) { appendHex(result, aBuf); } return result.toString(); } private static void appendHex(StringBuffer sb, byte b) { final String HEX = "0123456789ABCDEF"; sb.append(HEX.charAt((b >> 4) & 0x0f)).append(HEX.charAt(b & 0x0f)); } }