Membuat gradien di netbeans (komputer grafik)

public class MencobaGradien extends javax.swing.JFrame {

public void paint(Graphics g){

    super.paint(g);

    Graphics2D g2d = (Graphics2D)g;

    GradientPaint gp1 = new GradientPaint(5,5,

            Color.red,20,20, Color.black);

    g2d.setPaint(gp1);

    g2d.fillRect(20,20,300,40);

    GradientPaint gp2 = new GradientPaint(5,25,

            Color.yellow,20,2, Color.black,true);

    g2d.setPaint(gp2);

    g2d.fillRect(20,80,300,40);

    GradientPaint gp3 = new GradientPaint(5,25,

            Color.green,2,2, Color.black,true);

    g2d.setPaint(gp3);

    g2d.fillRect(20,140,300,40);

    GradientPaint gp4 = new GradientPaint(0,25,

            Color.blue,25,25, Color.black,true);

    g2d.setPaint(gp4);

    g2d.fillRect(20,260,300,40);

    GradientPaint gp5 = new GradientPaint(0,0,

            Color.orange,0,20, Color.black,true);

    g2d.setPaint(gp5);

    g2d.fillRect(20,20,300,40);

    //fill elipse2D.Double

    GradientPaint warnaku = new GradientPaint(50,50,Color.red,100,0,Color.white);

    g2d.setPaint(warnaku);

    g2d.fill(new Ellipse2D.Double(50,50,100,50));

}