getOppositeWindow() method returning null from Window Focus events

While switching focus between java frames, WINDOW_GAINED_FOCUS, WINDOW_LOST_FOCUS, WINDOW_ACTIVATED, and WINDOW_DEACTIVATED events are generated as expected. However, getOppositeWindow() method is always returning null.

- This is occuring on Solaris 2.7, Solaris IA 2.7, and Linux platforms. This bug does not occur on Win98.

- The bug occurs with either AWT Frame or Swing JFrame.

- Tested with build jdk1.4 Build 40

Steps to reproduce:

1) Compile and run attached sample code "AwtOppositeWindow.java"

2) After GUI comes up, just click back and forth on each window and observe the window focus events generated.


rick.reynaga@eng 2000-11-16
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Attaching AwtOppositeWindow.java sample to reporduce bug:

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.util.*;

public class AwtOppositeWindow extends Frame implements FocusListener, ActionListener, WindowFocusListener {

Frame frame1, frame2;
Button button1, button2;
TextArea textarea1, textarea2;
Checkbox chkbox;
java.awt.List list;

Component focusGainedWindow=null;
Component focusLostWindow=null;

KeyboardFocusManager manager;

public AwtOppositeWindow() {

manager = KeyboardFocusManager.getCurrentKeyboardFocusManager();

frame1 = new Frame("TestFrame1");
frame1.setLayout(new FlowLayout());
frame1.setSize(200,200);
frame1.setBackground(Color.orange);

frame2 = new Frame("TestFrame2");
frame2.setLayout(new FlowLayout());
frame2.setSize(200,200);
frame2.setBackground(Color.pink);

button1 = new Button("Button 1");
button1.addFocusListener(this);
button1.addActionListener(this);

button2 = new Button("Button 2");
button2.addFocusListener(this);

textarea1 = new TextArea("TextArea", 3,10);
textarea1.addFocusListener(this);

textarea2 = new TextArea("TextArea", 3,10);
textarea2.addFocusListener(this);

list = new java.awt.List(2);
list.add("Item 1");
list.add("Item 2");
list.addFocusListener(this);

chkbox = new Checkbox("Checkbox", false);
chkbox.addFocusListener(this);

frame1.add(button1);
frame1.add(textarea1);
frame1.add(list);

frame2.add(button2);
frame2.add(textarea2);
frame2.add(chkbox);

frame1.setLocation(0,50);
frame1.setVisible(true);
frame1.addWindowListener(this);

frame2.setLocation(0,250);
frame2.setVisible(true);
frame2.addWindowListener(this);
        
}

public void actionPerformed(ActionEvent ae) { }

public void windowGainedFocus(WindowEvent we) {
System.out.println("\n** windowGainedFocus Method" );
                focusLostWindow = we.getOppositeWindow();
                if (focusLostWindow == null) {
                    System.out.println("** Warning: getOppositeWindow() is null");
                }
                System.out.println(we);
}

public void windowLostFocus(WindowEvent we) {
System.out.println("\n** windowLostFocus Method" );
                focusGainedWindow = we.getOppositeWindow();
                if (focusGainedWindow == null) {
                    System.out.println("** Warning: getOppositeWindow() is null");
                }
                System.out.println(we);
        }

public void windowActivated(WindowEvent we){
System.out.println("\n** windowActivated Method" );
                if (we.getOppositeWindow() == null) {
                    System.out.println("** Warning: getOppositeWindow() is null");
                }
                System.out.println(we);
}

public void windowDeactivated(WindowEvent we){
System.out.println("\n** windowDeactivated Method" );
                if (we.getOppositeWindow() == null) {
                    System.out.println("** Warning: getOppositeWindow() is null");
                }
                System.out.println(we);
}
        
        public void windowOpened(WindowEvent we) { }
public void windowClosing(WindowEvent we) { }
public void windowClosed(WindowEvent we) { }
public void windowIconified(WindowEvent we) { }
public void windowDeiconified(WindowEvent we) { }

        public void focusLost(FocusEvent fe){ }
public void focusGained(FocusEvent fe) { }

public static void main(String args[]) {
new AwtOppositeWindow();
    }
}