import javax.swing.*;import java.awt.*;import java.awt.event.*;import java.beans.*;/* * SplitPaneDividerDemo.java is a 1.4 application that requires the following files: *   SizeDisplayer.java *   images/Cat.gif *   images/Dog.gif */public class SplitPaneDividerDemo extends JPanel                                  implements ActionListener {    private JSplitPane splitPane;        public SplitPaneDividerDemo() {        super(new BorderLayout());        Font font = new Font("Serif", Font.ITALIC, 24);        ImageIcon icon = createImageIcon("images/Cat.gif");        SizeDisplayer sd1 = new SizeDisplayer("left", icon);        sd1.setMinimumSize(new Dimension(30,30));        sd1.setFont(font);                icon = createImageIcon("images/Dog.gif");        SizeDisplayer sd2 = new SizeDisplayer("right", icon);        sd2.setMinimumSize(new Dimension(60,60));        sd2.setFont(font);                splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,                                   sd1, sd2);        splitPane.setResizeWeight(0.5);        splitPane.setOneTouchExpandable(true);        splitPane.setContinuousLayout(true);                add(splitPane, BorderLayout.CENTER);        add(createControlPanel(), BorderLayout.PAGE_END);    }    private JComponent createControlPanel() {        JPanel panel = new JPanel();        JButton reset = new JButton("Reset");        reset.addActionListener(this);        panel.add(reset);        return panel;    }        //Required by ActionListener interface. Respond to reset button.    public void actionPerformed(ActionEvent e) {        splitPane.resetToPreferredSizes();    }        /** Returns an ImageIcon, or null if the path was invalid. */    private static ImageIcon createImageIcon(String path) {        java.net.URL imgURL = SplitPaneDividerDemo.class.getResource(path);        if (imgURL != null) {            return new ImageIcon(imgURL);        } else {            System.err.println("Couldn't find file: " + path);            return null;        }    }    /**     * 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);        //Create and set up the window.        JFrame frame = new JFrame("SplitPaneDividerDemo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //Create and set up the content pane.        SplitPaneDividerDemo newContentPane = new SplitPaneDividerDemo();        newContentPane.setOpaque(true); //content panes must be opaque        frame.setContentPane(newContentPane);        //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();            }        });    }}