Include is a description of a bug from Corel. They are only
testing HotJava on Solaris. I was able to reproduce it using
the 1.0.2 appletviewer. It works in netscape. I suspect the
problem is a 1.0.2 regression. Test case included below.


Overridding dialog.show() will make dialogs end up
in a deadlock on Unix's HotJava.

While JavaSoft's bug report on the modal dialog
suggests to override dialog.show() to get around a
win32 implementation bug, by doing so will cause
the same dialog to deadlock in HotJava on Unix.

I appended to this message a sample applet that
demonstrates this bug. If you run it in HotJava, it
will hang in both situations presented.

On our side, we will try to get rid of all the
show() overrides.

The bad thing is that we never suspected that this
would have been the problem. How can you think
that removing the following code would have fixed
the problem?:

public void show()
{
    super.show();
}

But this code was the killer!

When you have an idea of when this will be fixed,
let me know. Thanks.

Claude


/////////////////////////////////////////////////
/**
* Demonstrates the show() synchronize bug.
*
* Try this test under any browser on the Unix
platform.
* You have a sure hang:
*
* HotJava: both dialogs will hang.
* Others: Will hang if the override of
dialog.show() is synchronized
* (as documented in the javasoft's bug
reports)
*
*/

import java.awt.*;

public class DialogShowBug extends
java.applet.Applet
{

    public DialogShowBug()
    {
    }

    public void init()
    {
        new MyFrame();
    }
}


class MyFrame extends Frame
{

    public MyFrame()
    {
     resize(400, 200);
        MenuBar menuBar = new MenuBar();
        Menu menu = new Menu("test");
        menu.add(new MenuItem("Invoke NON
synchronized Show"));
        menu.add(new MenuItem("Invoke synchronized
Show"));
        menuBar.add(menu);
        setMenuBar(menuBar);
     show();
    }

    public boolean action(Event event, Object
eventParam)
    {
        String strLabel = (String)eventParam;
        if(strLabel.equals("Invoke NON synchronized
Show"))
        {
            Dialog dlg = new NonSyncDlg(this);
            dlg.show();
            return true;
        }
        else if(strLabel.equals("Invoke synchronized
Show"))
        {
            Dialog dlg = new SyncDlg(this);
            dlg.show();
            return true;
        }
        return super.action(event, eventParam);
    }
}

class Test extends Dialog
{
    Button button;

    public Test(Frame parent, String title)
    {
super(parent, title, true);
addNotify();
reshape(parent.bounds().x +10,
parent.bounds().y, 300, 100);
        setLayout(null);
        button = new Button("OK");
        button.reshape(insets().left +
10,insets().top + 50, 70, 28);
        add(button);
    }


    public boolean action(Event evt, Object what)
    {
     if(evt.arg.equals("OK"))
     {
     dispose();
     return true;
     }
     return super.action(evt, what);
    }
}

class NonSyncDlg extends Test
{
    public NonSyncDlg(Frame parent)
    {
super(parent, "Invoke NON synchronized
Show");
    }

    public void show()
    {
        super.show();
    }
}

class SyncDlg extends Test
{
    public SyncDlg(Frame parent)
    {
super(parent, "Invoke synchronized Show");
    }

    public synchronized void show()
    {
        super.show();
    }
}