Java:MD5 Hash

import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;public class MD5 {private MD5() {}public static String md5(String s) {if (s == null) {return null;}MessageDigest digest;StringBuffer hasHexString;try {digest = MessageDigest.getInstance("MD5");digest.update(s.getBytes(), 0, s.length());byte messageDigest[] = digest.digest();hasHexString = new StringBuffer();for (int i = 0; i < messageDigest.length; i++) {String hex = Integer.toHexString(0xFF & messageDigest[i]);if (hex.length() == 1)hasHexString.append('0');hasHexString.append(hex);}return hasHexString.toString();} catch (NoSuchAlgorithmException e) {e.printStackTrace();}return null;}}