Name: clC74495 Date: 03/31/98

=20
The method EventQueue.removeSourceEvents() which
has the following line of code:

=09if (entry.event.getSource().equals(source)) {

fails if getSource() returns null, which is the case if the
event has been unserialized.=A0

Here is a test case:

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

public class QueueTest extends java.applet.Applet implements MouseListener{

  Button openB;

  /**
   * This event exists only for the purpose of setting its
   * source field to null. In our system, posting deserialized
   * events to the queue has this effect.
   */
  class TestEvent extends ActionEvent {
    TestEvent(Object src) {
      super(src, 10000, "none");
      source =3D null;
    }
  }
  =20

  /**
   * The main() function puts up a window with a button in it
   */
  public static void main(String args[]) {
    Frame f =3D new Frame("QueueTest");
    QueueTest queueTest =3D new QueueTest();
    queueTest.init();
    queueTest.start();


    queueTest.openB =3D new Button("make Java crash");
    queueTest.openB.addMouseListener(queueTest);
    f.add("Center", queueTest.openB);
    f.setSize(300, 300);
    f.show();
  }

  /**
   * This listener method posts an event with a null source to the event
   * queue and then removes the button from its parent. Removing the
   * button has the effect of calling java.awt.EventQueue.removeSourceEvent=
s(),
   * which generates a NullPointerException because of the null source of
   * the event on the queue
   */
  public void mouseClicked(MouseEvent e) {
    TestEvent ev =3D new TestEvent(this);
    Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(ev);
    openB.getParent().remove(openB);
  }

  public void mouseEntered(MouseEvent e) {;}
  public void mouseExited(MouseEvent e) {;}
  public void mousePressed(MouseEvent e) {
  }
  public void mouseReleased(MouseEvent e) {;}
}

--

Here is a stack trace:

java.lang.NullPointerException
        at java.awt.EventQueue.removeSourceEvents(EventQueue.java:189)
        at java.awt.Component.removeNotify(Component.java:2525)
        at java.awt.Container.removeNotify(Container.java:1147)
        at java.awt.Container.removeNotify(Container.java:1147)
        at java.awt.Container.removeNotify(Container.java:1147)
        at java.awt.Container.remove(Container.java:345)
        at java.awt.Container.remove(Container.java:384)
        at java.awt.Container.addImpl(Container.java:291)
        at java.awt.Container.add(Container.java:189)
        at WhiteBoard.ToolFrame.dockInWB(ToolFrame.java:178)
        at WhiteBoard.ToolFrame.setVisible(ToolFrame.java:133)
        at WhiteBoard.WhiteBoard.initialize(WhiteBoard.java:106)
        at WhiteBoard.WhiteBoard.startInFrame(WhiteBoard.java:117)
        at ncsa.habanero.Collobject.setFrame(Collobject.java:213)
        at ncsa.habanero.Collobject.<init>(Collobject.java:141)
        at ncsa.habanero.Sharable.instantiate(Sharable.java:170)
        at ncsa.habanero.AddCollobjectAction.act(AddCollobjectAction.java:1=
18)
        at ncsa.habanero.Targetable.performAction(Targetable.java:125)
        at ncsa.habanero.tickets.Ticket.act(Ticket.java:165)
        at ncsa.habanero.granted.ActionGranted.dispatch(ActionGranted.java:=
117)
        at ncsa.habanero.EventDispatchThread.dispatchEvent(EventDispatchThr=
ead.j
ava:196)
        at ncsa.habanero.EventDispatchThread.dispatchEvent(EventDispatchThr=
ead.j
ava:151)
        at ncsa.habanero.EventDispatchThread.run(EventDispatchThread.java:2=
14)

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Carlos.Lucasius@Canada (Mar 31, 1998):
Verified that this bug exists exactly as described.

(Review ID: 26332)
======================================================================