public abstract void fillArc(int x, int y, int width, int height, int startAngle, int arcAngle)
Means that the method fillArc() is not actually implemented
in the Graphics class. Normally, this would mean that you would have
to implement (i.e., write) the fillArc() method before you
could use it. But, don't worry, all methods in the Graphics class have
already been implemented in the Windows operating system.