Graph plot in java..

import java.awt.BasicStroke;
import java.awt.Color;
import java.io.FileOutputStream;

import org.jfree.chart.*;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.DeviationRenderer;
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
("Performance test", "Encryption time", "Decryption time", xyDataset, PlotOrientation.VERTICAL, true, true, false);
chart.setBackgroundPaint (Color.white);
XYPlot plot = (XYPlot) chart.getPlot();
plot.setBackgroundPaint (Color.white);
plot.setDomainGridlinesVisible(true);
plot.setRangeGridlinesVisible(true);
plot.setDomainGridlinePaint(Color.blue);
plot.setRangeGridlinePaint(Color.green);
/*
DeviationRenderer renderer = new DeviationRenderer(true, false);
renderer.setSeriesStroke (0, new BasicStroke (3.0f, BasicStroke.CAP_ROUND,
BasicStroke.JOIN_ROUND));
renderer.setSeriesStroke (1, new BasicStroke (3.0f, BasicStroke.CAP_ROUND,
BasicStroke.JOIN_ROUND));
renderer.setSeriesStroke (2, new BasicStroke (3.0f, BasicStroke.CAP_ROUND,
BasicStroke.JOIN_ROUND));
renderer.setSeriesPaint(2, new Color(0x00, 0x00, 0x00));
renderer.setSeriesPaint(1, new Color(0x99, 0x00, 0x00));
renderer.setSeriesPaint(0, new Color(0x99, 0x99, 0x00));
renderer.setSeriesFillPaint(2, new Color(0x00, 0x00, 0x00));
renderer.setSeriesFillPaint(1, new Color(0x99, 0x00, 0x00));
renderer.setSeriesFillPaint(0, new Color(0x99, 0x99, 0x00));
renderer.setAlpha(0.25f);
plot.setRenderer(renderer);
*/
ValueAxis rangeAxis = plot.getRangeAxis();
rangeAxis.setTickMarkPaint(Color.black);




ChartFrame frame1=new ChartFrame("XYLine Chart",chart);
frame1.setVisible(true);
frame1.setSize(300,300);
}
}