And how can I write one?
From comments to my reply, this followed:
"What we had in the old days - An Applet and Application - is not available anymore."
Rubbish. It [An Applet and Application] is called an hybrid, and is alive and well. Ask on a separate question if you would like clarification.
Addendum: How does that work?
createGUI(), and it adds the returned panel to the extant top-level container.
initContainer()method, passing the enclosing top-level container as a parameter.
class Hybridthat has a static
fireup()method and a
WindowListenerfor error reporting.