question: public void actionPerformed ( java . awt . event . ActionEvent e ) { String command = e . getActionCommand ( ) ; if ( logger . isLoggable ( Level . FINE ) ) { logger . fine ( command ) ; } try { LayerPane pane = findSelectedPane ( ) ; if ( pane != null ) { moveLayer ( pane , command ) ; } } catch ( NullPointerException npe ) { } catch ( ArrayIndexOutOfBoundsException aioobe ) { } }
target:  Method associated with the ActionListener interface. This method listens for action events meant to change the order of the layers, as fired by the layer order buttons.