I have created a program to validate a Canadian S.I.N. using Luhn's Algorithm, and was wondering if there was any way to make it more efficient. From what i can tell, it is already extremely efficient, but any tips or advice will be greatly appreciated.import javax.swing.*;import java.awt.*;import java.awt.event.*;class SinChecker extends JFrame{ //naming variablesJTextField t1;private JLabel j, j1, j2, j3;ButtonListener bl1;ButtonListener2 bl2;public SinChecker (){ //Get the containerContainer c = getContentPane ();//Set absolute layoutc.setLayout (null);//Set Background Colorc.setBackground (Color.WHITE);//Creating label Guess my number textJLabel j = new JLabel (S.I.N. Validation Checker);j.setForeground (Color.BLUE);j.setFont (new Font (tunga, Font.BOLD, 24));j.setSize (270, 20);j.setLocation (30, 35);//Creating label Enter a number.....j1 = new JLabel (Enter your S.I.N. below.);j1.setFont (new Font (tunga, Font.PLAIN, 17));j1.setSize (270, 20);j1.setLocation (66, 60);//Creating a label InstuctionsJLabel j2 = new JLabel (Enter a 9-digit Social Insurance Number);j2.setFont (new Font (tunga, Font.PLAIN, 17));j2.setSize (270, 20);j2.setLocation (10, 165);//Creating a label InstuctionsJLabel j3 = new JLabel (with no spaces between the digits please.);j3.setFont (new Font (tunga, Font.PLAIN, 17));j3.setSize (270, 20);j3.setLocation (10, 180);//Creating TextField for x input guesst1 = new JTextField (10);t1.setSize (70, 30);t1.setLocation (100, 80);//creating 2 buttonsJButton b1 = new JButton (Proceed);b1.setSize (120, 30);b1.setLocation (70, 200);bl1 = new ButtonListener ();b1.addActionListener (bl1);JButton b2 = new JButton (Re-enter);b2.setSize (120, 30);b2.setLocation (70, 250);bl2 = new ButtonListener2 ();b2.addActionListener (bl2);//Place the components in the panec.add (j);c.add (j1);c.add (j2);c.add (j3);c.add (t1);c.add (b1);c.add (b2);//Set the title of the windowsetTitle (Social Insurance Number Checker);//Set the size of the window and display itsetSize (300, 350);setVisible (true);setDefaultCloseOperation (EXIT_ON_CLOSE);}//implement  first action listenerprivate class ButtonListener implements ActionListener{public void actionPerformed (ActionEvent e){    int a = Integer.parseInt (t1.getText ());    boolean evenDigit = false;   //alternates between true and false    int sum = 0; //accumulates the sum of the digits (as modified)    while (a > 0)    {        int nextDigit = a % 10; //grab the last digit        a = a / 10; //discard that digit        if (evenDigit)        {            //double it, then add the two digits of the result            nextDigit = 2 * nextDigit;            nextDigit = (nextDigit / 10) + (nextDigit % 10);        } // if(evenDigit)        sum = sum + nextDigit;        evenDigit = !evenDigit; //toggle the flag each time    } // end while    if (0 == sum % 10)    {        j1.setText (That is a valid S.I.N.);    }    else    {        j1.setText (That is not a valid S.I.N.);    }    t1.requestFocus ();    t1.selectAll ();}   } private class ButtonListener2 implements ActionListener {   public void actionPerformed (ActionEvent e)   {    //reset the label messages    t1.setText ();    j1.setText (Enter your S.I.N. below.);    t1.requestFocus ();    t1.selectAll ();}}public static void main (String[] args){  new SinChecker (); } }
A S.I.N checker, using Luhn's Algorithm, and created in swing.
java;algorithm;swing;checksum