/** * ClickMeApp.java is an application that compiles and runs * under J2SE v5.0.  It requires two additional files: *   ClickMe.java *   Spot.java */ import javax.swing.SwingUtilities;import javax.swing.JLabel;import javax.swing.JFrame;import java.awt.BorderLayout;public class ClickMeApp implements Runnable {        /**     * This constructor creates an instance of ClickMeApp,     * which creates and shows a window containing a     * ClickMe component.     */    public ClickMeApp() {        /*         * Tells the event-dispatching thread (used to         * display and handle events of a Swing GUI) to         * call the run method of "this" (the ClickMeApp         * object this constructor created).  The         * argument to invokeLater must implement the         * Runnable interface, which guarantees that         * it defines the run method.         */        SwingUtilities.invokeLater(this);    }        /**     * Creates and shows the GUI.  This method should be     * invoked on the event-dispatching thread.     */    public void run() {        createAndShowGUI();    }        /**     * Brings up a window that contains a ClickMe component.     * 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);        //Create and set up the window.        JFrame frame = new JFrame("ClickMeApp");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //Set up the layout manager.        frame.setLayout(new BorderLayout());                //Add the ClickMe component.        ClickMe component = new ClickMe();        frame.add(component, BorderLayout.CENTER);                //Add an explanatory label.        frame.add(new JLabel("Click within the rectangle."),                             BorderLayout.SOUTH);        //Display the window.        frame.pack();        frame.setVisible(true);    }    //This method is automatically executed.    public static void main(String[] args) {        //Create an instance of ClickMeApp.        new ClickMeApp();    }}