Java Swing tutorials.
Action Listeners are the most common and easiest event handlers for implementation. An action listener is implemented to detail that what could be possibly done when cetain operations are performed by user.
When a user performs an action, an action event takes place. For example, when a button is clicked by a user, menu item is choosen and in text field ENTER is pressed. An actionPerformed message would be sent to all of the action listeners , which on a relevant component are registered.