Hi friend,

Code to solve the problem :

import org.jfree.chart.*;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.data.xy.*;
import org.jfree.data.*;

public class xyLine{
public static void main(String arg[]){
XYSeries series = new XYSeries("Average Weight");
series.add(20.0, 20.0);
series.add(40.0, 25.0);
series.add(55.0, 50.0);
series.add(70.0, 65.0);
XYDataset xyDataset = new XYSeriesCollection(series);
JFreeChart chart = ChartFactory.createXYLineChart
("XYLine Chart using JFreeChart", "Age", "Weight",
xyDataset, PlotOrientation.VERTICAL, true, true, false);
ChartFrame frame1=new ChartFrame("XYLine Chart",chart);
frame1.setVisible(true);
frame1.setSize(300,300);
}
}

For more information,Examples and Tutorials on jfree chart visit to :

http://www.roseindia.net/chartgraphs/

Thanks