stroke = new BasicStroke(
             0.2f*ds,//width
             BasicStroke.CAP_ROUND,
             BasicStroke.JOIN_BEVEL);//don't care
    g2.setStroke(stroke);
    g2.setPaint(Color.green);
    g2.draw(new Line2D.Double(
               -1.5*ds,-1.0*ds,-0.5*ds,-1.0*ds));

Figure 4