Just a simple tip to draw curves in java using Piccolo2D(download the jar file from: piccolo2D) and the curve api (download the jar file from: Curve API):

List<Point2D> points = new ArrayList<Point2D>(); 
// Collect points 
Shape shape = new CurveCreator().getShape(points); 
PPath p = new PPath(); 
p.setPathTo(shape);