Some adapted version using recursion... Draw the circle, then draw its 2 children by calling the same function again.
void drawCircles(Graphics graphics, int xMid, int yMid, int radius) {
// end recursion
if(radius < 5)
return;
// Draw circle
graphics.drawOval(xMid - radius, yMid - radius, radius * 2, radius * 2);
// start recursion
//left
drawCircles(graphics, xMid-radius, yMid, radius / 2);
//right
drawCircles(graphics, xMid+radius, yMid, radius / 2);
}