JButton has a constructor that takes an action object. The action object determines a number of the button's properties. In our case the button icon, the caption and the action to be performed when the button is pressed is all determined by the Thumbn

The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available. See Java Language Changes for a summary of up

An Action object is an action listener that provides not only action-event handling, but also centralized handling of the state of action-event-firing components such as tool bar buttons, menu items, common buttons, and text fields. The state that an acti