Exemplo gráfico de pizza no JFreeChart

//Requirido a API do JFreeChart

import java.awt.Font;
import javax.swing.JFrame;
import javax.swing.JPanel;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PiePlot;
import org.jfree.data.general.DefaultPieDataset;

public class ChartFrame extends JFrame
{
private static final long serialVersionUID = 1L;
private DefaultPieDataset dataset;
private JFreeChart jfc;
public ChartFrame()

{
dataset = new DefaultPieDataset();
}

public void setValue(String title, Double numDouble)
{
dataset.setValue(title, numDouble);
}

public void setChar(String title)
{

jfc = ChartFactory.createPieChart(title, dataset, true, true, false);
PiePlot pp = (PiePlot) jfc.getPlot();
pp.setSectionOutlinesVisible(false);
pp.setLabelFont(new Font("SansSerif", Font.PLAIN, 12));
pp.setNoDataMessage("Nessun Dato Inserito");
pp.setCircular(false);
pp.setLabelGap(0.02);
}

private JPanel createPanel()
{
return new ChartPanel(jfc);
}

public void Show()
{
setContentPane(createPanel());
setVisible(true);
}

public static void main(String[] args)
{
ChartFrame j = new ChartFrame();
j.setTitle("Example Chart...");
j.setSize(640, 430);
j.setValue("UNO", new Double(20.0));
j.setValue("DUE", new Double(10.0));
j.setValue("TRE", new Double(20.0));
j.setValue("QUATTRO", new Double(30.0));
j.setValue("CINQUE", new Double(20.0));
j.setChar("Example Chart...");
j.Show();
}

}