frame=new JFrame();

Set old =
	frame.getFocusTraversalKeys( KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS );
AWTKeyStroke ks = 
	AWTKeyStroke.getAWTKeyStroke( KeyEvent.VK_N, InputEvent.CTRL_DOWN_MASK );
Set new = new HashSet( old );
set.add( ks );
frame.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,set);

//frame.setFocusableWindowState(false);
//frame.setFocusTraversalPolicy( new DefaultFocusTraversalPolicy() );
//frame.setFocusTraversalPolicy( new ContainerOrderFocusTraversalPolicy() );

frame.getContentPane().add( "Center", jt=new JTextField(10) );
jt.setFocusable(true);
frame.getContentPane().add( "North", jt=new JTextField(10) );
jt.setFocusable(true);
frame.getContentPane().add( "West", jt=new JTextField(10) );
jt.setFocusable(true);
frame.getContentPane().add( "South", jt=new JTextField(10) );
jt.setFocusable(true);

frame.pack();
frame.setVisible(true);