import java.io.*;
import java.text.*;
import org.jfree.chart.*;
import org.jfree.chart.plot.*;
import org.jfree.chart.axis.*;
import org.jfree.data.category.*;
import org.jfree.chart.renderer.category.*;
import org.jfree.chart.labels.StandardCategoryItemLabelGenerator;

public class ChartDemo{

   public static void main(String arg[]){
      File f1=new File("C:\\");
      File f2=new File("D:\\");
      long d1 = f1.getFreeSpace()/1024/1024;
      long d2 = f2.getFreeSpace()/1024/1024;
      DefaultCategoryDataset dataset = new DefaultCategoryDataset();
      dataset.setValue(d1, "Free Space", "C");
      dataset.setValue(d2, "Free Space", "D");
      JFreeChart chart = ChartFactory.createBarChart("Bar Chart","Drives", "Free Space(in MB)", dataset, 
      PlotOrientation.VERTICAL, false,true, false);
      CategoryPlot p = chart.getCategoryPlot(); 
      NumberAxis rangeAxis = (NumberAxis) p.getRangeAxis();
      rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
      BarRenderer renderer = (BarRenderer) p.getRenderer();
      DecimalFormat decimalformat1 = new DecimalFormat("##");
      renderer.setItemLabelGenerator(new StandardCategoryItemLabelGenerator("{2}", decimalformat1));
      renderer.setItemLabelsVisible(true);
      chart.getCategoryPlot().setRenderer(renderer);
      ChartFrame frame=new ChartFrame("Bar Chart",chart);
      frame.setVisible(true);
      frame.setSize(350,450);
    }
 }