/* * SwingApplication.java is a 1.4 example that requires * no other files. */import javax.swing.*;          import java.awt.*;import java.awt.event.*;public class SwingApplication implements ActionListener {    private static String labelPrefix = "Number of button clicks: ";    private int numClicks = 0;    final JLabel label = new JLabel(labelPrefix + "0    ");    //Specify the look and feel to use.  Valid values:    //null (use the default), "Metal", "System", "Motif", "GTK+"    final static String LOOKANDFEEL = null;    public Component createComponents() {        JButton button = new JButton("I'm a Swing button!");        button.setMnemonic(KeyEvent.VK_I);        button.addActionListener(this);        label.setLabelFor(button);        /*         * An easy way to put space between a top-level container         * and its contents is to put the contents in a JPanel         * that has an "empty" border.         */        JPanel pane = new JPanel(new GridLayout(0, 1));        pane.add(button);        pane.add(label);        pane.setBorder(BorderFactory.createEmptyBorder(                                        30, //top                                        30, //left                                        10, //bottom                                        30) //right                                        );        return pane;    }    public void actionPerformed(ActionEvent e) {        numClicks++;        label.setText(labelPrefix + numClicks);    }    private static void initLookAndFeel() {        String lookAndFeel = null;        if (LOOKANDFEEL != null) {            if (LOOKANDFEEL.equals("Metal")) {                lookAndFeel = UIManager.getCrossPlatformLookAndFeelClassName();            } else if (LOOKANDFEEL.equals("System")) {                lookAndFeel = UIManager.getSystemLookAndFeelClassName();            } else if (LOOKANDFEEL.equals("Motif")) {                lookAndFeel = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";            } else if (LOOKANDFEEL.equals("GTK+")) { //new in 1.4.2                lookAndFeel = "com.sun.java.swing.plaf.gtk.GTKLookAndFeel";            } else {                System.err.println("Unexpected value of LOOKANDFEEL specified: "                                   + LOOKANDFEEL);                lookAndFeel = UIManager.getCrossPlatformLookAndFeelClassName();            }            try {                UIManager.setLookAndFeel(lookAndFeel);            } catch (ClassNotFoundException e) {                System.err.println("Couldn't find class for specified look and feel:"                                   + lookAndFeel);                System.err.println("Did you include the L&F library in the class path?");                System.err.println("Using the default look and feel.");            } catch (UnsupportedLookAndFeelException e) {                System.err.println("Can't use the specified look and feel ("                                   + lookAndFeel                                   + ") on this platform.");                System.err.println("Using the default look and feel.");            } catch (Exception e) {                System.err.println("Couldn't get specified look and feel ("                                   + lookAndFeel                                   + "), for some reason.");                System.err.println("Using the default look and feel.");                e.printStackTrace();            }        }    }    /**     * Create the GUI and show it.  For thread safety,     * this method should be invoked from the     * event-dispatching thread.     */    private static void createAndShowGUI() {        //Set the look and feel.        initLookAndFeel();        //Make sure we have nice window decorations.        JFrame.setDefaultLookAndFeelDecorated(true);        //Create and set up the window.        JFrame frame = new JFrame("SwingApplication");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        SwingApplication app = new SwingApplication();        Component contents = app.createComponents();        frame.getContentPane().add(contents, BorderLayout.CENTER);        //Display the window.        frame.pack();        frame.setVisible(true);    }    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();            }        });    }}