Implementation of java MD5 encryption code

Code

package util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class HashUtil {

   private static MessageDigest digest = null;

    public synchronized static final String hash(String data) {
        if (digest == null) {
            try {
                digest = MessageDigest.getInstance("MD5");
            } catch (NoSuchAlgorithmException nsae) {
                System.err.println("Failed to load the MD5 MessageDigest. " +
                        "Jive will be unable to function normally.");
                nsae.printStackTrace();
            }
        }
        // Now, compute hash.
        digest.update(data.getBytes());
        return encodeHex(digest.digest());
    }

    public static final String encodeHex(byte[] bytes) {
        StringBuffer buf = new StringBuffer(bytes.length * 2);
        int i;

        for (i = 0; i < bytes.length; i++) {
            if (((int) bytes[i] & 0xff) < 0x10) {
                buf.append("0");
            }
            buf.append(Long.toString((int) bytes[i] & 0xff, 16));
        }
        return buf.toString();
    }

    public static final byte[] decodeHex(String hex) {
        char[] chars = hex.toCharArray();
        byte[] bytes = new byte[chars.length / 2];
        int byteCount = 0;
        for (int i = 0; i < chars.length; i += 2) {
            byte newByte = 0x00;
            newByte |= hexCharToByte(chars[i]);
            newByte <<= 4;
            newByte |= hexCharToByte(chars[i + 1]);
            bytes[byteCount] = newByte;
            byteCount++;
        }
        return bytes;
    }
    
    private static final byte hexCharToByte(char ch) {
        switch (ch) {
            case '0':
                return 0x00;
            case '1':
                return 0x01;
            case '2':
                return 0x02;
            case '3':
                return 0x03;
            case '4':
                return 0x04;
            case '5':
                return 0x05;
            case '6':
                return 0x06;
            case '7':
                return 0x07;
            case '8':
                return 0x08;
            case '9':
                return 0x09;
            case 'a':
                return 0x0A;
            case 'b':
                return 0x0B;
            case 'c':
                return 0x0C;
            case 'd':
                return 0x0D;
            case 'e':
                return 0x0E;
            case 'f':
                return 0x0F;
        }
        return 0x00;
    }

}

transfer

    public static void main(String[] args)
   {
      String pwd = "aabbcc";
      String pwdMd5 =  HashUtil.hash(pwd);
      System.out.println(pwdMd5);
   }

Output

61a60170273e74a5be90355ffe8e86ad