System.exit(0) has been removed from BaseGame.quit(). It has been added to BaseSimpleGame.quit() so that all SimpleGame subclasses will continue to exit normally. This was done to give people more control of the exiting procedures of their BaseGame subclassed games. So, if you are extending BaseGame you might want to add:
protected void quit() {
super.quit();
System.exit(0);
}
to your subclass.