INR to USD Converter

import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JTextField;
import java.awt.event.ActionEvent;
import javax.swing.SwingUtilities;
import java.awt.event.ActionListener;

/**
 *
 * @author toffe boy Aamir
 */
public class CurrencyExchange extends JPanel implements ActionListener{
    public JButton change;
    public JTextField ind,usa;
    CurrencyExchange(){
        super(new FlowLayout());
        ind = new JTextField(20);
        ind.setText("250");
        usa = new JTextField(20);
        usa.setEditable(false);
        change = new JButton("Convert");
        add(ind);add(change);add(usa);
        change.addActionListener(this);

    }

    @Override
    public void actionPerformed(ActionEvent e) {

        final double USD = 0.0148993;
        final double INR = Double.parseDouble(ind.getText());
        //1 INR = 0.0148993 USD (24/08/2016)
        // check the current status http://www.xe.com/currencyconverter/convert/?Amount=1&From=INR&To=USD
        usa.setText(Double.toString(INR*USD) +" USD");

    }


    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                CurrencyExchange.showGUI();
            }
        });
    }


    private static void showGUI() {
        JFrame gui = new JFrame("INR to USD");
        gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JComponent newContentPane = new CurrencyExchange();
        newContentPane.setOpaque(true);
        gui.setContentPane(newContentPane);
        gui.setResizable(false);
        gui.setVisible(true);
        gui.pack();
    }
}