public class AvailabilitySearchFrame extends JFrame {
...
} // end class def 

public class RemoteAvailabilitySearchFrame extends AvailabilitySearchFrame { 
...
} // end class def 

new RemoteAvailabilitySearchFrame();

 Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException 
at javax.swing.LayoutComparator.compare(Unknown Source) 
at java.util.Arrays.mergeSort(Unknown Source) 
at java.util.Arrays.sort(Unknown Source) 
at java.util.Collections.sort(Unknown Source) 
at javax.swing.SortingFocusTraversalPolicy.enumerateAndSortCycle(Unknown Source) 
at javax.swing.SortingFocusTraversalPolicy.getFirstComponent(Unknown Source) 
at javax.swing.LayoutFocusTraversalPolicy.getFirstComponent(Unknown Source) 
at javax.swing.SortingFocusTraversalPolicy.getDefaultComponent(Unknown Source) 
at java.awt.FocusTraversalPolicy.getInitialComponent(Unknown Source) 
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source) 
at java.awt.Component.dispatchEvent(Unknown Source) 
at java.awt.EventQueue.dispatchEvent(Unknown Source) 
at java.awt.SequencedEvent.dispatch(Unknown Source) 
at java.awt.EventQueue.dispatchEvent(Unknown Source) 
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source) 
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) 
at java.awt.EventDispatchThread.pumpEvents(Unknown Source) 
at java.awt.EventDispatchThread.pumpEvents(Unknown Source) 
at java.awt.EventDispatchThread.run(Unknown Source)  

 super();

	public AvailabilitySearchFrame() { // default constructor
 
	     super();
 
	     buildGUI(); // create and add frame components
 
	     this.setFocusable(true);
	     this.addKeyListener(new EnterListener());
	     this.addMouseListener(new FrameMouseListener());
 
	     rightClickMenu.disablePropertyDetailsItem();
 
	     this.setSize(1024, 768);    		
	     this.pack();
              this.setLocationRelativeTo(null);	
	     this.setDefaultCloseOperation(EXIT_ON_CLOSE);
 
	     this.setVisible(true);
 
	} // end default constructor

	public RemoteAvailabilitySearchFrame() { // default constructor
 
	     super();
 
	     setTitle("Remote System - " + title);
 
	     searchPanel.remove(criteriaPanel);
 
	     mainJMenuBar.remove(propertiesJMenu);
	     mainJMenuBar.remove(ownersJMenu);
	     mainJMenuBar.remove(cleanersJMenu);
	     mainJMenuBar.remove(financialsJMenu);
	     mainJMenuBar.remove(analysisJMenu);
 
	     reservationJMenu.remove(newReservationJMenuItem);
	     reservationJMenu.remove(mergeRemoteFilesJMenuItem);
	     reservationJMenu.remove(reservationAnalysisJMenuItem);
	     reservationJMenu.remove(yearJMenuItem);
 
	     toDoListJMenuItem.removeActionListener(toDoListJMenuItemListener);
	     toDoListJMenuItem.addActionListener(new RemoteToDoListJMenuItemListener());
 
	} // end default constructor

package net.SloanVentures.util;
import javax.swing.JPanel;
import java.awt.Component;
 
public class PanelComponentsEnabler {
 
	public static void enablePanelComponents(JPanel panel, boolean state) {
 
		Component[] components = panel.getComponents();
		for (int i=0; i < components.length; i++) {
			Component component = (Component) components[i];
 
			// if child component is a sub-panel, make a recursive call
			if (component.getClass().toString().equals("class javax.swing.JPanel")) {
				JPanel subPanel = (JPanel) component;
				enablePanelComponents(subPanel, state);
			} else {
				component.setEnabled(state);
			} // end if
 
		} // end for
 
	} // end enablePanelComponents
 
} // end class def