A Panel is a fairly generic Container
whose primary purpose is to subdivide the drawing area into
separate rectangular pieces. Since each Panel can have
its own LayoutManager, you can do many things with
panels that you can't do with a single LayoutManager.
For example, suppose you want a TextArea in the
center of an applet with a Button below, like
this:
There's no single LayoutManager that will produce
this. A BorderLayout will expand the
Button to fill the entire width of the applet. A
FlowLayout won't make the TextArea big
enough.