A Window is a lightweight top-level container that can be used to hold other AWT components. It provides a way to create a separate window without the additional features of a frame, such as a title ...

Swing一些底层类使用AWT的Component、Container、Window等类，可能是为了保持与AWT兼容，方便大家将代码移植到Swing上. Swing不再沿用Peer对等模式来实现GUI界面，完全基于Java自绘制图形实现。

When this window closes, I want it to call the function 'closeListener(java.awt.event.WindowEvent e)' and do some extra stuff before I dispose the frame and exit.