FocusListener « Swing Event « Java Tutorial

15.16.1.The FocusListener Interface: respond to a component gaining or losing the focus
15.16.2.The event IDs defined in the FocusEvent class
15.16.3.How to Write a Focus ListenerHow to Write a Focus Listener
15.16.4.FocusListener and FocusEvent
15.16.5.Validating a JTextField When Permanently Losing the Focus
15.16.6.Use Focus Events in Swing
15.16.7.Validate a value on the lostFocus event