Name: iaR10016 Date: 10/10/2000



JDK version:
java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0)
Java HotSpot(TM) Client VM (build 1.3.0, mixed mode)

The following test example creates JFrame with JMenu component.
To reproduce the bug please select menu and then try to select any menu item.

The following error message appears unexpectedly when you move mouse to the item:

...

$ java test
Exception occurred during event dispatching:
java.lang.ArrayIndexOutOfBoundsException
        at javax.swing.MenuSelectionManager.processMouseEvent(MenuSelectionManager.java:238)
        at javax.swing.plaf.basic.BasicMenuUI$MouseInputHandler.mouseDragged(BasicMenuUI.java:370)
        at java.awt.AWTEventMulticaster.mouseDragged(AWTEventMulticaster.java:260)
        at java.awt.Component.processMouseMotionEvent(Component.java:3761)
        at javax.swing.JComponent.processMouseMotionEvent(JComponent.java:2377)
        at java.awt.Component.processEvent(Component.java:3550)
        at java.awt.Container.processEvent(Container.java:1164)
        at java.awt.Component.dispatchEventImpl(Component.java:2595)
        at java.awt.Container.dispatchEventImpl(Container.java:1213)
        at java.awt.Component.dispatchEvent(Component.java:2499)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:2451)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:2205)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2125)
        at java.awt.Container.dispatchEventImpl(Container.java:1200)
        at java.awt.Window.dispatchEventImpl(Window.java:912)
        at java.awt.Component.dispatchEvent(Component.java:2499)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:333)
        at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:103)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:84)
Exception occurred during event dispatching:
java.lang.ArrayIndexOutOfBoundsException
        at javax.swing.MenuSelectionManager.processMouseEvent(MenuSelectionManager.java:238)
        at javax.swing.plaf.basic.BasicMenuUI$MouseInputHandler.mouseDragged(BasicMenuUI.java:370)
        at java.awt.AWTEventMulticaster.mouseDragged(AWTEventMulticaster.java:260)
        at java.awt.Component.processMouseMotionEvent(Component.java:3761)
        at javax.swing.JComponent.processMouseMotionEvent(JComponent.java:2377)
        at java.awt.Component.processEvent(Component.java:3550)
        at java.awt.Container.processEvent(Container.java:1164)
        at java.awt.Component.dispatchEventImpl(Component.java:2595)
        at java.awt.Container.dispatchEventImpl(Container.java:1213)
        at java.awt.Component.dispatchEvent(Component.java:2499)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:2451)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:2205)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2125)
        at java.awt.Container.dispatchEventImpl(Container.java:1200)
        at java.awt.Window.dispatchEventImpl(Window.java:912)
        at java.awt.Component.dispatchEvent(Component.java:2499)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:333)
        at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:103)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:84)
Exception occurred during event dispatching:
java.lang.ArrayIndexOutOfBoundsException
        at javax.swing.MenuSelectionManager.processMouseEvent(MenuSelectionManager.java:238)
        at javax.swing.plaf.basic.BasicMenuUI$MouseInputHandler.mouseDragged(BasicMenuUI.java:370)
        at java.awt.AWTEventMulticaster.mouseDragged(AWTEventMulticaster.java:260)
        at java.awt.Component.processMouseMotionEvent(Component.java:3761)
        at javax.swing.JComponent.processMouseMotionEvent(JComponent.java:2377)
        at java.awt.Component.processEvent(Component.java:3550)
        at java.awt.Container.processEvent(Container.java:1164)
        at java.awt.Component.dispatchEventImpl(Component.java:2595)
        at java.awt.Container.dispatchEventImpl(Container.java:1213)
        at java.awt.Component.dispatchEvent(Component.java:2499)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:2451)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:2205)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2125)
        at java.awt.Container.dispatchEventImpl(Container.java:1200)
        at java.awt.Window.dispatchEventImpl(Window.java:912)
        at java.awt.Component.dispatchEvent(Component.java:2499)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:333)
        at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:103)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:84)
...

Please note that if the JMenu.setSelected(true) method call is commented, the test works fine.

------------------------- test.java ---------------------------------------------
import java.awt.*;
import javax.swing.*;

public class test {
    public static void main (String [] args ) {
        JFrame frame = new JFrame();
        frame.setSize(new Dimension(200,300));
        JMenu menu = new JMenu("Menu");
        menu.add("Item 1");
        menu.add("Item 2");
        menu.add("Item 3");
        menu.setSelected(true);
        JMenuBar menuBar = new JMenuBar();
        menuBar.add(menu);
        frame.getContentPane().add( menuBar, BorderLayout.CENTER );
        frame.setVisible(true);
    }
}

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