Java Help! pls

[Rain Man]

Well im doing my java assignment and im on track for finishing it really. Just stuck on one piece of code.

Im using java elements and i need to draw an object, clear it, and redraw it slights further on to create the animation. And...it wont work.
--------------------------------------------------------------------------
int XCENTRE=(800);
int YCENTRE=(330);
int RADIUS=(20);
DrawingWindow d = new DrawingWindow(850,350);
Circle C = new Circle(XCENTRE,YCENTRE,RADIUS);


for (XCENTRE = 800; XCENTRE >=400; XCENTRE = XCENTRE-1) {

d.setForeground(Color.black);
d.fill(C);

}
---------------------------------

pls help thanks