Having JFrame's with the same JMenuBar instance

Question

Like the title suggests, I'd like to have exactly one JMenuBar used in multiple JFrame's. This however doesn't seem to work. Whenever adding the JMenuBar instance to a second JFrame makes the menu disappear from the first JFrame.

See my SSCCE:

public class MenuTest extends JPanel {
    private static final long serialVersionUID = -9209142740183347797L;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI(); 
            }
        });
    }

    private static void createAndShowGUI() {
        System.out.println("Created GUI on EDT? "+ SwingUtilities.isEventDispatchThread());

        JMenuBar bar = new JMenuBar();
        bar.add(new JMenu("Test1"));
        bar.add(new JMenu("Test2"));
        bar.add(new JMenu("Test3"));

        JFrame f = new JFrame("Swing Paint Demo 1");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new MenuTest());
        f.setJMenuBar(bar);
        f.pack();
        f.setVisible(true);


        JFrame f2 = new JFrame("Swing Paint Demo 2");
        f2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f2.add(new MenuTest());
        f2.setJMenuBar(bar);
        f2.pack();
        f2.setVisible(true);
    }
}

Might this be possible or is this prohibited?

See [The Use of Multiple JFrames, Good/Bad Practice?](http://stackoverflow.com/q/9554636/418556) — Andrew Thompson, Aug 05 '14 at 07:07

score 4 · Accepted Answer · edited May 23 '17 at 12:11

This can't be done, at least not the way you want to.

A component may belong to only a single parent container, this means the moment you try applying it to a second container, it will effectively remove it from the previous container.

Instead of trying to maintain a single instance, instead, consider using a "builder" or "factory" pattern which generates new instances of the JMenuBar for you.

Too make life easier, I would suggest having a look at How to Use Actions

Also have a look at The Use of Multiple JFrames, Good/Bad Practice?

Having JFrame's with the same JMenuBar instance

1 Answers1