Re: any recommendations?

Knute Johnson <>
Sun, 04 Feb 2007 17:28:12 -0800
Brandon McCombs wrote:


Somewhere in my code I have a bug that I can't reliably reproduce. It
occurs randomly when I'm deleting entries from a JList (I retrieve
certain pieces of info from the entry before deleting it, then I delete
it and the JList contents are then refreshed so remaining items are
re-added to the JList). The only output I get when the exception occurs
is the following:

Exception in thread "AWT-EventQueue-0"
java.lang.ArrayIndexOutOfBoundsException: 1 >= 0
    at java.util.Vector.elementAt(Unknown Source)
    at javax.swing.DefaultListModel.getElementAt(Unknown Source)
    at javax.swing.plaf.basic.BasicListUI.paintCell(Unknown Source)
    at javax.swing.plaf.basic.BasicListUI.paint(Unknown Source)
    at javax.swing.plaf.ComponentUI.update(Unknown Source)
    at javax.swing.JComponent.paintComponent(Unknown Source)
    at javax.swing.JComponent.paint(Unknown Source)
    at javax.swing.JComponent.paintWithOffscreenBuffer(Unknown Source)
    at javax.swing.JComponent.paintDoubleBuffered(Unknown Source)
    at javax.swing.JComponent._paintImmediately(Unknown Source)
    at javax.swing.JComponent.paintImmediately(Unknown Source)
    at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
    at java.awt.event.InvocationEvent.dispatch(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at Source)

The "1" as the index value differs between exception printouts. I don't
know where that index value is originating from or what Vector is really
having its elements retrieved. The index value doesn't correspond to
the index of the Object that I'm selecting for deletion. I've placed
try/catches throughout the places where I thought was causing the
exception to print out a stacktrace that I hoped would include a line
number but I'm not getting any extra output. I also would put in a print
statement so I knew which try/catch was being executed but I don't see
that outputted either.

When the JList is refreshed it is done so through a thread. I've tried
to use run() to make the thread do its work but not in a thread and I
don't get the exception but since I can't reproduce it reliably I don't
know if it's really a threading problem or not. Using Eclipse's
debugger also doesn't help so far because I can't get the error to occur
during the debugging, at least not yet.

Is there anything else I can try that can give me more information as to
what line in my code this is occurring on so I can begin to fix it?


Are you modifying the JList on the EDT? Are you modifying the Vector
after creating your JList? Can you make a simple test program that
demonstrates the problem?


Knute Johnson
email s/nospam/knute/

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