Hi Friend,

Use rs.getDouble() method to retrieve marks and percentage.

import java.sql.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Test extends JFrame{
public static void main(String[]args){

try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con1 =DriverManager.getConnection("jdbc:odbc:access","","");
Statement stmt=con1.createStatement();
double marks=80.58;
double percent=80.58;
int i=stmt.executeUpdate("insert into student1(marks,percentage) values("+marks+","+percent+")");
JOptionPane.showMessageDialog(null,"Data is successfully inserted into database.");
ResultSet rs=stmt.executeQuery("select * from student1 where id=1");
double m=0;
double p=0;
while (rs.next())
{
m=rs.getDouble("marks");
p=rs.getDouble("percentage");
}
System.out.println(m);
System.out.println(p);


}

catch(Exception e){
System.out.println(e);
}
}
}

Thanks