Copyright (c) SEMM NL All rights reserved.
Author : Paul Hamaker. Part of

This class extends javax.swing.JPanel , so it cannot function on its own.

To run it standalone, we subclass a javax.swing.JFrame.

This is created in the stand-alone entry point, the main method ...

and our panel is added to it as its contentpane.

We must make the frame visible, because by default it's not !

To make the frame closable, we use an adapter without a name, an anonymous one.

Notice the syntax.

It's the argument to addWindowListener.