The follow implementation self-starts, and is also somewhat faster.

	    public void fillFast(int x, int y, int fill)
	    {
	        if ((x < 0) || (x >= raster.width)) return;
	        if ((y < 0) || (y >= raster.height)) return;
	        int old = raster.getPixel(x, y);
	        if (old == fill) return;
	        raster.setPixel(fill, x, y);
	        fillEast(x+1, y, fill, old);
	        fillSouth(x, y+1, fill, old);
	        fillWest(x-1, y, fill, old);
	        fillNorth(x, y-1, fill, old);
	    }