After opening the user application, "Ichitaro Ark",
  I tried to select a file with pull down menu fuction,
  and then the stack trace showed up in MS-DOS window.
  At this time, I could select and open the file.
  But once closed the application, the next time re-opening the
  application, I could not select any file and the error dialog
  with the message "java.lang.NullPointerException" appeared.
 
 < Configration >
  
    1. Operating Sysytem
        Windows95(OSR2),Windows98 and WindowsNT4.0
        
    2. JDK version
        java version "1.3.0"
        Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-F)
        Java(TM) HotSpot Client VM (build 1.3FCS-F, mixed mode)
  
 < More Information >
  - Stack trace list
    The following list is derived from the case on WinNT.
    Here, "ark0607.jar" is the user's application "Ichitaro Ark" and
    "D:\users2\PGM\just_files>" is prompt.

--- Stack Trace list ----

D:\users2\PGM\just_files>java -jar ark0607.jar
Exception occurred during event dispatching:
java.lang.NullPointerException
        at java.awt.Container.remove(Container.java:465)
        at javax.swing.JTable.removeEditor(JTable.java:3548)
        at javax.swing.JTable.columnMarginChanged(JTable.java:2851)
        at javax.swing.table.DefaultTableColumnModel.fireColumnMarginChanged(Def
aultTableColumnModel.java:532)
        at javax.swing.table.DefaultTableColumnModel.propertyChange(DefaultTable
ColumnModel.java:564)
        at javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(Swing
PropertyChangeSupport.java:157)
        at javax.swing.table.TableColumn.firePropertyChange(TableColumn.java:228
)
        at javax.swing.table.TableColumn.firePropertyChange(TableColumn.java:234
)
        at javax.swing.table.TableColumn.setWidth(TableColumn.java:444)
        at javax.swing.JTable$3.setSizeAt(JTable.java:2111)
        at javax.swing.JTable$6.setSizeAt(JTable.java:2196)
        at javax.swing.JTable.adjustSizes(JTable.java:2232)
        at javax.swing.JTable.adjustSizes(JTable.java:2200)
        at javax.swing.JTable.setWidthsFromPreferredWidths(JTable.java:2119)
        at javax.swing.JTable.sizeColumnsToFit(JTable.java:2077)
        at javax.swing.JTable.doLayout(JTable.java:1922)
        at java.awt.Container.validateTree(Container.java:737)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validateTree(Container.java:744)
        at java.awt.Container.validate(Container.java:719)
        at java.awt.Window.dispatchEventImpl(Window.java:849)
        at java.awt.Component.dispatchEvent(Component.java:2460)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:322)
        at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:10
7)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:97)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:88)

--- Stack Trace list End -----

tbaba@japan 1999-09-14

=============================================================================