Is this a bug..?

[shahabas shabeer]

Hi friends,

I downloded a java file from sun's swing tutorial. (http://java.sun.com/docs/books/tutorial/uiswing/components/example-1dot4/MenuLookDemo.java)

I edited the code and added the following two lines.

menu.setBackground(Color.RED);// This is the first line that I added
submenu.setBackground(Color.GREEN);// This is the seccond line that I added

It worked as expected when I tested with java version "1.4.2_04"
But, unfortunately, it is not working with java version "1.5.0"
The background color is set properly when I use java version other than "1.5.0"
But when I use java version "1.5.0", The back ground is still the default background color.

Am I doing anything wrong..?
Or is this a bug..?
I tested in windows 98 and XP. Both produced the same result.
So I guess the problem is with jre.
Here is the code

  
import java.awt.*;
import java.awt.event.*;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JCheckBoxMenuItem;
import javax.swing.JRadioButtonMenuItem;
import javax.swing.ButtonGroup;
import javax.swing.JMenuBar;
import javax.swing.KeyStroke;
import javax.swing.ImageIcon;
 
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;
import javax.swing.JFrame;
 
/* MenuLookDemo.java is a 1.4 application that requires images/middle.gif. */
 
/*
 * This class exists solely to show you what menus look like.
 * It has no menu-related event handling.
 */
public class MenuLookDemo {
    JTextArea output;
    JScrollPane scrollPane;
 
    public JMenuBar createMenuBar() {
        JMenuBar menuBar;
        JMenu menu, submenu;
        JMenuItem menuItem;
        JRadioButtonMenuItem rbMenuItem;
        JCheckBoxMenuItem cbMenuItem;
 
        //Create the menu bar.
        menuBar = new JMenuBar();
 
        //Build the first menu.
        menu = new JMenu("A Menu");
        menu.setMnemonic(KeyEvent.VK_A);
        menu.getAccessibleContext().setAccessibleDescription(
                "The only menu in this program that has menu items");

        [B]menu.setBackground(Color.RED);// This is the first line that I added[/B]
        menuBar.add(menu);
 
        //a group of JMenuItems
        menuItem = new JMenuItem("A text-only menu item",
                                 KeyEvent.VK_T);
        //menuItem.setMnemonic(KeyEvent.VK_T); //used constructor instead
        menuItem.setAccelerator(KeyStroke.getKeyStroke(
                KeyEvent.VK_1, ActionEvent.ALT_MASK));
        menuItem.getAccessibleContext().setAccessibleDescription(
                "This doesn't really do anything");
        menu.add(menuItem);
 
        ImageIcon icon = createImageIcon("images/middle.gif");
        menuItem = new JMenuItem("Both text and icon", icon);
        menuItem.setMnemonic(KeyEvent.VK_B);
        menu.add(menuItem);
 
        menuItem = new JMenuItem(icon);
        menuItem.setMnemonic(KeyEvent.VK_D);
        menu.add(menuItem);
 
        //a group of radio button menu items
        menu.addSeparator();
        ButtonGroup group = new ButtonGroup();
 
        rbMenuItem = new JRadioButtonMenuItem("A radio button menu item");
        rbMenuItem.setSelected(true);
        rbMenuItem.setMnemonic(KeyEvent.VK_R);
        group.add(rbMenuItem);
        menu.add(rbMenuItem);
 
        rbMenuItem = new JRadioButtonMenuItem("Another one");
        rbMenuItem.setMnemonic(KeyEvent.VK_O);
        group.add(rbMenuItem);
        menu.add(rbMenuItem);
 
        //a group of check box menu items
        menu.addSeparator();
        cbMenuItem = new JCheckBoxMenuItem("A check box menu item");
        cbMenuItem.setMnemonic(KeyEvent.VK_C);
        menu.add(cbMenuItem);
 
        cbMenuItem = new JCheckBoxMenuItem("Another one");
        cbMenuItem.setMnemonic(KeyEvent.VK_H);
        menu.add(cbMenuItem);
 
        //a submenu
        menu.addSeparator();
        submenu = new JMenu("A submenu");
        submenu.setMnemonic(KeyEvent.VK_S);

        [B]submenu.setBackground(Color.GREEN);// This is the seccond line that I added[/B]

        menuItem = new JMenuItem("An item in the submenu");
        menuItem.setAccelerator(KeyStroke.getKeyStroke(
                KeyEvent.VK_2, ActionEvent.ALT_MASK));
        submenu.add(menuItem);
 
        menuItem = new JMenuItem("Another item");
        submenu.add(menuItem);
        menu.add(submenu);
 
        //Build second menu in the menu bar.
        menu = new JMenu("Another Menu");
        menu.setMnemonic(KeyEvent.VK_N);
        menu.getAccessibleContext().setAccessibleDescription(
                "This menu does nothing");
        menuBar.add(menu);
 
        return menuBar;
    }
 
    public Container createContentPane() {
        //Create the content-pane-to-be.
        JPanel contentPane = new JPanel(new BorderLayout());
        contentPane.setOpaque(true);
 
        //Create a scrolled text area.
        output = new JTextArea(5, 30);
        output.setEditable(false);
        scrollPane = new JScrollPane(output);
 
        //Add the text area to the content pane.
        contentPane.add(scrollPane, BorderLayout.CENTER);
 
        return contentPane;
    }
 
    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) {
        java.net.URL imgURL = MenuLookDemo.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("MenuLookDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
        //Create and set up the content pane.
        MenuLookDemo demo = new MenuLookDemo();
        frame.setJMenuBar(demo.createMenuBar());
        frame.setContentPane(demo.createContentPane());
 
        //Display the window.
        frame.setSize(450, 260);
        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();
            }
        });
    }
}

Thanks
Shahabas E Shabeer

[Craig Wood]

The evaluation in this bug report points toward the change from j2se 1.4 to 1.5

Method setBackground() does not work when JMenu is a submenu

which is that JMenu is non–opaque by default in j2se 1.5 to accomodate the Ocean LookAndFeel. You can try this before you instantiate any menus

import javax.swing.UIManager;
import javax.swing.plaf.ColorUIResource;
    ...
    UIManager.put("Menu.opaque", Boolean.TRUE);
    // possibly in conjunction with something like this
    UIManager.put("Menu.background", new ColorUIResource(Color.red));

As an aside, this is why it is recommended that we call setOpaque(true) on any JComponent that is used as an argument in the JFrame setContentPane method.

[Ken Blair]

Indeed, at this point it's a good rule of thumb to explicitly set components opaque (or not opaque) because what they instantiate to is not always predictable. As the above poster hinted at, this can be a problem with JPanel's as well, especially when used for a content pane.

[shahabas shabeer]

Yes .. you are right..
I think the transparancy of the component depends on the look and feel used.
The code that I posted worked fine when I set native look and feel than the default swing look and feel.
I do now believe that it is always better to explicitly set the transparancy of the component.
Thanks a lot for all your help
cheers
Shahabas E Shabeer