FULL PRODUCT VERSION :
java version "1.6.0_02"
Java(TM) SE Runtime Environment (build 1.6.0_02-b06)
Java HotSpot(TM) Client VM (build 1.6.0_02-b06, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Windows XP SP3

A DESCRIPTION OF THE PROBLEM :
Originally bug 4801718. The problem has re-occured in the particular build shown above.

I have a project which was left in a working state in March 2008 and when I returned to it July 2008 after (presumably) updates have been automatically applied to my JRE/JDK it is no longer working

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a class that extends JList - call the JList default constructor with super() then a simple method such as

    public DefaultListModel getDefaultListModel()
    {
        return (DefaultListModel) getModel();
    }

will result in a class cast exception javax.swing.JList$3 cannot be cast to DefaultListModel

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
getModel() should return a form of AbstractListModel (specifically ListModel in the JList source)
ACTUAL -
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: javax.swing.JList$3 cannot be cast to javax.swing.DefaultListModel


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------

import javax.swing.DefaultListModel;
import javax.swing.JList;

/**
 * Steps to reproduce re occurred bug 4801718
 * @author LLINCOLN
 */
public class BugRep extends JList{

    public BugRep()
    {
        super();
    }

    public DefaultListModel getDefaultModel()
    {
        return (DefaultListModel) getModel();
    }

    public static void main(String[] args)
    {
        BugRep rep = new BugRep();
        rep.getDefaultModel();
    }

}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
call super(new DefaultListModel()); in the constructor.