Thread: how to plot a line graph by reading the values from database?

hello
I have a database consisting of datetime of type timestamp and memory used of int.
Database(test4.test) consists of
15 2012-02-03 15:14:43
12 2012-05-06 16:17:46

But we are unable to plot a graph showing the errors saying
Exception in thread "main" java.lang.ClassCastException: java.sql.Timestamp cannot be cast to java.sql.Date
at org.jfree.data.jdbc.JDBCCategoryDataset.executeQue ry(JDBCCategoryDataset.java: at org.jfree.data.jdbc.JDBCCategoryDataset.executeQue ry(JDBCCategoryDataset.java: at Chart1.main(Chart1.java:26)
Java Result: 1
How to resolve this error.
the following code we have used

import java.sql.*;
import java.io.*;
import org.jfree.ui.*;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.*;
import org.jfree.data.jdbc.JDBCCategoryDataset;

public class Chart1 {
public static void main(String[] args) throws Exception {
String query = "SELECT * from test";
JDBCCategoryDataset dataset = new JDBCCategoryDataset( "jdbc:mysql://localhost:3306/test4", "com.mysql.jdbc.Driver","root", "root");
dataset.executeQuery(query);
JFreeChart chart = ChartFactory.createLineChart("Test", "Id", "Score", dataset, PlotOrientation.VERTICAL, true, true, false);
ChartPanel chartPanel = new ChartPanel(chart);
chartPanel.setPreferredSize(new java.awt.Dimension(500, 270));
ApplicationFrame f = new ApplicationFrame("Chart");
f.setContentPane(chartPanel);
f.pack();
f.setVisible(true);
}
}

please tel what is the error and how to resolve it

how to convert Timestamp to java.sql.date ?please tell me

if we put data type as DATE .date value is not storing in database..it shows above error
Value '0000-00-00' can not be represented as java.sql.Date
please resolve this error.

if we put data type as DATE .date value is not storing in database..it shows below error
Value '0000-00-00' can not be represented as java.sql.Date
please resolve this error.

we resolved this problems...

how to construct a instance of java.sql.Date using long representation.please give some sample code of it