Name: mf23781 Date: 03/02/98


java_g for an AWT application causes:

AWT lock error (./../../../../src/unix/sun/awt_Frame.c,772) (last held by ./../../../../src/unix/sun/awt_Frame
.c,742) 1
AWT unlock error (./../../../../src/unix/sun/awt_Frame.c,839,1)

A simple HelloWorld awt application causes the problem.

eg:

import java.awt.*;
import java.awt.event.*;

public class hwawt extends Frame
         implements ActionListener
    {
    public Button goodbyeButton;

    public hwawt()
       {
       // Listen for window events - such as closing
       setLayout(new FlowLayout());
       TextArea t = new TextArea("Hello World !", 6, 40);
       goodbyeButton = new Button("GoodBye");
       setTitle("Brians AWT HelloWorld Application");
            add(t);
            add(goodbyeButton);
       goodbyeButton.addActionListener(this);
       setSize(400, 200);
            show();
    }

    public static void main(String args[]) {
        hwawt window = new hwawt();
    }

    // ActionListener
    public void actionPerformed(ActionEvent e) {
            if (e.getSource() == goodbyeButton) {
          dispose();
          System.exit(0);
       }
       return;
    }
}

The problem is in awt_Frame.c
Method sun_awt_motif_MFramePeer_addTextComponent get the AWT_LOCK then calls
sun_awt_motif_MFramePeer_pReshape. This also get the AWT_LOCK.
When we compile the DEBUG version, awt.h defines AWT_LOCK to include some checking.
Basically it increments a counter (awt_locked) each time the lock is obtained and decrements
it each time the lock is released. If this count was not zero before we try and obtain the
lock the error message is issued.

So a question for Sun:
Is it valid to obtain the AWT_LOCK twice ? If so, the
 jio_fprintf(stderr, "AWT lock error (%s,%d) (last held by %s,%d) %d\n"
in awt.h is incorrect.

Coincidentally, the call to sun_awt_motif_MFramePeer_pReshape in
sun_awt_motif_MFramePeer_addTextComponent which is causing the problem, has been removed in
defect 4372 (Sunbug: 4113040) - for a completely different reason !






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