/** * CelsiusConverter.java is a 1.4 application that  * demonstrates the use of JButton, JTextField and * JLabel.  It requires no other files. */import java.awt.*;import java.awt.event.*;import javax.swing.*;public class CelsiusConverter implements ActionListener {    JFrame converterFrame;    JPanel converterPanel;    JTextField tempCelsius;    JLabel celsiusLabel, fahrenheitLabel;    JButton convertTemp;    public CelsiusConverter() {        //Create and set up the window.        converterFrame = new JFrame("Convert Celsius to Fahrenheit");        converterFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        converterFrame.setSize(new Dimension(120, 40));        //Create and set up the panel.        converterPanel = new JPanel(new GridLayout(2, 2));        //Add the widgets.        addWidgets();        //Set the default button.        converterFrame.getRootPane().setDefaultButton(convertTemp);        //Add the panel to the window.        converterFrame.getContentPane().add(converterPanel, BorderLayout.CENTER);        //Display the window.        converterFrame.pack();        converterFrame.setVisible(true);    }    /**     * Create and add the widgets.     */    private void addWidgets() {        //Create widgets.        tempCelsius = new JTextField(2);        celsiusLabel = new JLabel("Celsius", SwingConstants.LEFT);        convertTemp = new JButton("Convert");        fahrenheitLabel = new JLabel("Fahrenheit", SwingConstants.LEFT);        //Listen to events from the Convert button.        convertTemp.addActionListener(this);        //Add the widgets to the container.        converterPanel.add(tempCelsius);        converterPanel.add(celsiusLabel);        converterPanel.add(convertTemp);        converterPanel.add(fahrenheitLabel);                celsiusLabel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));        fahrenheitLabel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));    }    public void actionPerformed(ActionEvent event) {        //Parse degrees Celsius as a double and convert to Fahrenheit.        int tempFahr = (int)((Double.parseDouble(tempCelsius.getText()))                             * 1.8 + 32);        fahrenheitLabel.setText(tempFahr + " Fahrenheit");    }    /**     * Create the GUI and show it.  For thread safety,     * this method should be invoked from the     * event-dispatching thread.     */    private static void createAndShowGUI() {        //Make sure we have nice window decorations.        JFrame.setDefaultLookAndFeelDecorated(true);        CelsiusConverter converter = new CelsiusConverter();    }    public static void main(String[] args) {        //Schedule a job for the event-dispatching thread:        //creating and showing this application's GUI.        javax.swing.SwingUtilities.invokeLater(new Runnable() {            public void run() {                createAndShowGUI();            }        });    }}