Exception in thread "main" java.lang.NullP ointerException

hi all,

i'm using the following code and i'm getting
exception in thread "main" java.lang.nullp ointerexception at the line which is in bold. help me to solve this problem

import java.applet.*;
import java.awt.*;
import java.io.*;
import javax.swing.*;
import java.sql.*;
import java.awt.event. *;
import sun.jdbc.odbc.* ;
public class Customerdetails extends Frame implements ActionListener
{
TextField ccod,cname,add, phno,conp,email ,fax;
Label l1,l2,l3,l4,l5, l6,l7;
Button save,exit;
Connection con;
ResultSet rs;
Statement stmt;

String s1,s2,s3,s4,s5, s6,s7;

public Customerdetails ()
{
super("Customer Details");
setSize(800,800 );
setLayout(new GridLayout(7,2, 45,45));
l1=new Label("Customer code");
l2=new Label("CompanyN ame");
l3=new Label("Address" );
l4=new Label("PhoneNum ber");
l5=new Label("Contact person");
l6=new Label("EmailAdd ress");
l7=new Label("FaxNumbe r");

add(l1);
add(ccod);
add(l2);
add(cname);
add(l3);
add(add);
add(l4);
add(phno);
add(l5);
add(conp);
add(l6);
add(email);
add(l7);
add(fax);

save.addActionL istener(this);
exit.addActionL istener(this);
setVisible(true );



addWindowListen er(new WindowAdapter() {
public void WindowClosing(W indowEvent w) {System.exit(0) ;}});
}
public void actionPerformed (ActionEvent ae)
{

if(ae.getSource ()==save)
{
s1=ccod.getText ();
s2=cname.getTex t();
s3=add.getText( );
s4=phno.getText ();
s5=conp.getText ();
s6=email.getTex t();
s7=fax.getText( );

try
{
String query = "insert into Customerdetails (Customercode,C ompanyName,Addr ess,PhoneNumber ,Contact person,EmailAdd ress,FaxNumber) "+
"values('"+s1+" ','"+s2+"','"+s 3+"','"+s4+"',' "+s5+"','"+s6+" ','"+s7+"')";
Class.forName(" sun.jdbc.odbc.J dbcOdbcDriver") ;
con=DriverManag er.getConnectio n("jdbc:odbc:pr ism");
stmt=con.create Statement();
rs=stmt.execute Query(query);
stmt.close();
}
catch(ClassNotF oundException e)
{
System.out.prin tln(e);
}
catch(SQLExcept ion e)
{
System.out.prin tln(e);
}
}
if(ae.getSource ()==exit)
{
System.exit(0);
}
}
public static void main(String args[])
{

Customerdetails cd=new Customerdetails ();
}
}