SHA-1/MD5/MAC NetBeans

//SHA-1
private static String byteArrToString(byte[] b){
        String res = null;
        StringBuffer sb = new StringBuffer(b.length * 2);
        for (int i = 0; i < b.length; i++){
           int j = b[i] & 0xff;
           if (j < 16) {
              sb.append('0');
           }
           sb.append(Integer.toHexString(j));
        }
        res = sb.toString();
        return res.toUpperCase();
     }

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        String passwordSHA = null;
        MessageDigest sha = null;
        try {
            sha = MessageDigest.getInstance("SHA-1");
        } catch (NoSuchAlgorithmException ex) {
            Logger.getLogger(SHA.class.getName()).log(Level.SEVERE, null, ex);
        }
        byte[] tmp = jTextArea1.getText().getBytes();
        sha.update(tmp);
        String textSHA = byteArrToString(sha.digest());
        jTextField1.setText(textSHA);
    }


//MD5
 public static String toHex(byte [] digest) {
        StringBuffer hexString = new StringBuffer();
        for(int i = 0; i<digest.length; i++)
        {
            hexString.append(Integer.toHexString(0xFF & digest[i]));
        }
        return new String(hexString);
    }


    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {

        MessageDigest messageDigest = null;
        try {
            messageDigest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException ex) {
            Logger.getLogger(MD5.class.getName()).log(Level.SEVERE, null, ex);
        }
        String text;
        text = jTextArea1.getText();
        byte[] plaintext = null;
        try {
            plaintext = text.getBytes("UTF8");
        } catch (UnsupportedEncodingException ex) {
            Logger.getLogger(MD5.class.getName()).log(Level.SEVERE, null, ex);
        }
        messageDigest.update(plaintext);
        byte[] msgDigest = messageDigest.digest();
        String digest = toHex(msgDigest);
        jTextField1.setText(digest);
    }

//MAC

public static String toHex(byte [] digest) {
        StringBuffer hexString = new StringBuffer();
        for(int i = 0; i<digest.length; i++)
        {
            hexString.append(Integer.toHexString(0xFF & digest[i]));
        }
        return new String(hexString);
    }

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        KeyGenerator keyGen = null;
        try {
            keyGen = KeyGenerator.getInstance("HmacMD5");
        } catch (NoSuchAlgorithmException ex) {
            Logger.getLogger(MAC.class.getName()).log(Level.SEVERE, null, ex);
        }
        SecretKey MD5key = keyGen.generateKey();

        String text;
        text = jTextArea1.getText();
        byte[] plaintext = null;

        try {
            plaintext = text.getBytes("UTF8");
        } catch (UnsupportedEncodingException ex) {
            Logger.getLogger(MD5.class.getName()).log(Level.SEVERE, null, ex);
        }
        Mac mac = null;
        try {
            mac = Mac.getInstance("HmacMD5");
        } catch (NoSuchAlgorithmException ex) {
            Logger.getLogger(MAC.class.getName()).log(Level.SEVERE, null, ex);
        }
        try {
            mac.init(MD5key);
        } catch (InvalidKeyException ex) {
            Logger.getLogger(MAC.class.getName()).log(Level.SEVERE, null, ex);
        }
        mac.update(plaintext);

        byte[] byteMacFinal = mac.doFinal();
        String macFinal = toHex(byteMacFinal);
        jTextField1.setText(macFinal);
    }