From about 15 seconds into the video (link below) Notch starts apparently coding while the game is running - and having it magically reflect his changes. I tried to stop/start the video in a sort of frame by frame manner. I notice just before he starts doing it, a properties window of some sort pops up but I’m too slow to catch it. I can see that he’s using Eclipse and I understand that he uses LWJGL for his games, right? The make-up of the game seems to be an applet (I have limited experience with applets).
Does anyone know how he does that? Is the application actually updating to reflect code changes without having to go through the close/build/run sequence?