Java md5 example with MessageDigest

StringBuffer sb=new StringBuffer();
for (int i = 0; i < bytes.length; i++) {
     String hex=Integer.toHexString(0xff & bytes[i]);
     if(hex.length()==1) sb.append('0');
     sb.append(hex);
}

import java.security.*;

... etc

String pass = "123456";


byte[] defaultBytes = pass.getBytes();
try{
     MessageDigest algorithm = MessageDigest.getInstance("MD5");
     algorithm.reset();
     algorithm.update(defaultBytes);
     byte messageDigest[] = algorithm.digest();

     StringBuffer hexString = new StringBuffer();
     for (int i=0;i<messageDigest.length;i++) {
	String hex = Integer.toHexString(0xFF & messageDigest[i]); 
	if(hex.length()==1)
	hexString.append('0');

	hexString.append(hex);
     }
						     
						     
     //*** Testausgabe
     System.out.println("pass "+pass+"   md5 version is "+hexString.toString());
     pass = hexString+"";
}
catch(NoSuchAlgorithmException nsae){
						                    
}

package test;

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

public class MD5Test
{
    public static void main(String[] args)
    {
        String md5val = "";
        MessageDigest algorithm = null;

        try
        {
            algorithm = MessageDigest.getInstance("MD5");
        }
        catch (NoSuchAlgorithmException nsae)
        {
            System.out.println("Cannot find digest algorithm");
            System.exit(1);
        }
        
        for (String arg : args)
        {
            byte[] defaultBytes = arg.getBytes();
            algorithm.reset();
            algorithm.update(defaultBytes);
            byte messageDigest[] = algorithm.digest();
            StringBuffer hexString = new StringBuffer();

            for (int i = 0; i < messageDigest.length; i++)
            {
                String hex = Integer.toHexString(0xFF & messageDigest[i]);
                if (hex.length() == 1)
                {
                    hexString.append('0');
                }
                hexString.append(hex);
            }
            md5val = hexString.toString();
            System.out.println("MD5 ("" + arg + "") = " + md5val);
        }
    }
}

g@h ~/bin$ md5 -s dammitjanet
MD5 ("dammitjanet") = ea309a2eb146a4d8bdf8946c4df23c71
g@h ~/bin$ java -cp . test.MD5Test dammitjanet
MD5 ("dammitjanet") = ea309a2eb146a4d8bdf8946c4df23c71

g@h ~/bin$ java -cp . test.MD5Test "bark at the moon"  
SHA-256 ("bark at the moon") = a5bb786220762b74c9569cd9f150a4176f9da3c2ac29d776a65487b2a77d4429

    static String getMd5Digest(String input)
        {
            try
            {
                MessageDigest md = MessageDigest.getInstance("MD5");
                byte[] messageDigest = md.digest(input.getBytes());
                BigInteger number = new BigInteger(1,messageDigest);
                return number.toString(16);
            }
            catch(NoSuchAlgorithmException e)
            {
                throw new RuntimeException(e);
            }
        }

import java.security.*;
import java.io.*;
import java.math.BigInteger;

public class Checksum {

    //
    // returns 0 error
    //         1 ok (create)
    //         1 same (check)
    //         2 different (check)
    //
    public static void main(String args[]) {
        if (args.length == 2) {
            if (args[0].equalsIgnoreCase("create")) {
                System.exit(new Checksum().create(args[1]));
            } else if (args[0].equalsIgnoreCase("check")) {
                System.exit(new Checksum().check(args[1]));
            }
        } else {
            System.out.println("Usage : java Checksum create [filename]n" +
                    "        java Checksum check  [filename]");
        }
    }

    public int create(String filename) {
        try {
            int sum;
            String salida = new String();
            byte[] chk = createChecksum(filename);
            File f = new File(filename + ".chk");
            OutputStream os = new FileOutputStream(f);
            //muestra la cadena MD5 y es la misma quela del program MD5Check.exe
            BigInteger bigInt = new BigInteger(1, chk);
            String output = bigInt.toString(16).toUpperCase();;
            if (output.length() < 32){
				System.out.println("Menor de 32");
                sum = 32 - output.length();
                for ( int i = 1 ; i == sum;i++){
                    salida=salida.concat("0");
                }
                salida = salida.concat(output);
            }
            System.out.println("MD5: " + output+" = "+ salida);
            os.write(chk);
            os.close();
            return 1;
        } catch (Exception e) {
            e.printStackTrace();
            return 0;
        }
    }

    public int check(String filename) {
        int rc = 0;
        try {
            byte[] chk1 = createChecksum(filename);
            byte[] chk2 = new byte[chk1.length];
            File f = new File(filename + ".chk");
            InputStream is = new FileInputStream(f);

            is.read(chk2);
            //muestra la cadena MD5 y es la misma quela del program MD5Check.exe
            BigInteger bigInt1 = new BigInteger(1, chk1);
            String output1 = bigInt1.toString(16).toUpperCase();;
            System.out.println("MD5: " + filename + "     " + output1);
            BigInteger bigInt2 = new BigInteger(1, chk2);
            String output2 = bigInt2.toString(16).toUpperCase();;
            System.out.println("MD5: " + filename + ".chk " + output2);
            //fin muestra
            //if (new String(chk2).equals(new String(chk1))) {
            if (output2.equals(output1)) {
                System.out.println("Same!");
                rc = 1;
            } else {
                System.out.println("Different!");
                rc = 2;
            }
            is.close();
            return rc;
        } catch (Exception e) {
            e.printStackTrace();
            return rc;
        }
    }

    public byte[] createChecksum(String filename) throws Exception {
        InputStream fis = new FileInputStream(filename);

        byte[] buffer = new byte[1024];
        MessageDigest complete = MessageDigest.getInstance("MD5");
        int numRead;
        do {
            numRead = fis.read(buffer);
            if (numRead > 0) {
                complete.update(buffer, 0, numRead);
            }
        } while (numRead != -1);
        fis.close();
        return complete.digest();
    }
}