Hiding and restoring table columns from file?

Question

how i handle hiding and unhiding columns in a jtable is that i have a checkbox for each column, depending on which is checked "on" the tablecolumn is found and added to a vector and removed from the table.
when the checkbox is checked "off" this vector is searched for the correct tablecolumn, and then added back to the table. this works fine.
when i close out of the program, i go thru the table and write the visible column names along with its size to file.
when i re-open the program, i create the table normally, then go thru the file and hide(remove) the tablecolumns found in it..this works fine.
but when i go back to this checkbox list and try to unhide the tablecolumn, i get an exception
java.lang.IllegalArgumentException: Cannot format given Object as a Number
     at java.text.NumberFormat.format(NumberFormat.java:219)
     at java.text.Format.format(Format.java:133)
     at javax.swing.JTable$DoubleRenderer.setValue(JTable.java:3397)
     at javax.swing.table.DefaultTableCellRenderer.getTableCellRendererComponent(DefaultTableCellRenderer.java:160)
     at javax.swing.JTable.prepareRenderer(JTable.java:3731)
     at javax.swing.plaf.basic.BasicTableUI.paintCell(BasicTableUI.java:1149)
     at javax.swing.plaf.basic.BasicTableUI.paintCells(BasicTableUI.java:1051)
     at javax.swing.plaf.basic.BasicTableUI.paint(BasicTableUI.java:974)
     at javax.swing.plaf.ComponentUI.update(ComponentUI.java:142)
     at javax.swing.JComponent.paintComponent(JComponent.java:541)
     at javax.swing.JComponent.paint(JComponent.java:808)
     at javax.swing.JComponent.paintChildren(JComponent.java:647)
     at javax.swing.JComponent.paint(JComponent.java:817)
     at javax.swing.JViewport.paint(JViewport.java:722)
     at javax.swing.JComponent.paintChildren(JComponent.java:647)
     at javax.swing.JComponent.paint(JComponent.java:817)
     at javax.swing.JComponent.paintWithOffscreenBuffer(JComponent.java:4787)
     at javax.swing.JComponent.paintDoubleBuffered(JComponent.java:4740)
     at javax.swing.JComponent._paintImmediately(JComponent.java:4685)
     at javax.swing.JComponent.paintImmediately(JComponent.java:4488)
     at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:410)
     at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:117)
     at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:178)
     at java.awt.EventQueue.dispatchEvent(EventQueue.java:454)
     at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
     at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)before i unhide the columns, the table is already populated with values. so it might have something to do with that...cuz there is no problems unhiding them if the table contains no data
any ideas?
thanks

Answer 1

If you're interested, this method hides a table column without any modifications of its content:
   public static void setTableColumnVisible(JTable table, int col,                                                                             
                                              boolean visible, int width) {
      try {
         TableColumn column = table.getColumnModel().getColumn(col);
         if (!visible) {
            column.setMinWidth(0);
            column.setWidth(0);
            column.setMaxWidth(0);
            column.setPreferredWidth(0);
         else {
            column.setWidth(width);
            column.setPreferredWidth(width);
      catch(Exception e) {
         e.printStackTrace();
   }Method use:
. setTableColumnVisible(table, col, false, 0) hides the column
. setTableColumnVisible(table, col, true, 100) restores the column to its size of 100
Hope this helped,
Regards.