A swing demo source code available at http://java.sun.com/docs/books/tutorial/ui/overview/PasswordStore-1.0-src.zip
or at http://java.sun.com/docs/books/tutorial/ui/overview/demo.html
contains a few Javadoc errors and one error in the code:

        public FilterUndo(ExtendedUndoManager unodManager, String filterString) {
            super(undoManager);
            this.filterString = filterString;
            subsumeNextSelection = true;
        }

The first parameter in the method should be "undoManager".

I've attached fixed sources of the whole example. Please, review my changes and updated the code on the site if they are correct