Ellipse2D.Double circle4 = 
        new Ellipse2D.Double(
                     0.0*ds,0.0*ds,2.0*ds,2.0*ds);
    g2.setPaint(
        new GradientPaint(
           0.0f*ds,0.0f*ds,Color.red,
           0.25f*ds,0.25f*ds,Color.orange,true));
    g2.fill(circle4);
    g2.draw(circle4);

Figure 6