Java SE (Java Platform, Standard Edition)

I was using the default formatters for the following field and this worked fine.

{
      jOpNumTxtFld = new JFormattedTextField();                    
      jOpNumTxtFld.setValue( new Integer(0) );
      jOpNumTxtFld.addPropertyChangeListener("value", 
              new PropertyChangeListener()  {
                  public void propertyChange( PropertyChangeEvent evt ) {
                      int old = ((Integer)evt.getOldValue()).intValue();
                      int nwV = ((Integer)evt.getNewValue()).intValue();
                      if( old != nwV )  {  
                          opNum = nwV;
                      }
}

But I didn't like the group separator that the default formatters use so, on the suggestion of the
[How to Use Formatted Text Fields|http://java.sun.com/docs/books/tutorial/uiswing/components/formattedtextfield.html#factory] tutorial, I defined my own DefaultFormatterFactory:

{
          NumberFormat opnDisplayFormat = NumberFormat.getIntegerInstance();
          opnDisplayFormat.setGroupingUsed( false );
          NumberFormat opnEditFormat = NumberFormat.getIntegerInstance();
          opnEditFormat.setGroupingUsed( false );
          jOpNumTxtFld = new JFormattedTextField(
                    new DefaultFormatterFactory(
                        new NumberFormatter( opnDisplayFormat ),
                        new NumberFormatter( opnDisplayFormat ),
                        new NumberFormatter( opnEditFormat )));    
          jOpNumTxtFld.setValue( new Integer(0) );
          jOpNumTxtFld.addPropertyChangeListener("value", 
                    new PropertyChangeListener()  {
                        public void propertyChange( PropertyChangeEvent evt ) {
                            int old = ((Integer)evt.getOldValue()).intValue();
                            int nwV = ((Integer)evt.getNewValue()).intValue();
                            if( old != nwV )  {  
                                opNum = nwV;
                            }
}

Formats are now just how I like them. BUT now the control insists on translating an entered string into a Long. For instance, the first time the field loses focus I get a ClassCastException on +(Integer)evt.getNewValue()+. Only four digits are allowed in the field so a Long is pointless as well as being a pain in the butt to deal with.

What the heck is going on? And if there's a batter way to accomplish this please inform.