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 ();
}
}
18 2558
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 ();
}
}
1.) Use code tags when posting code.
2.) Your constructor dereferences variables that are not initialized. See the buttons for example.
Hi pradeep84,
Welcome to TSDN!
Do you know why does this happen?
Have a look at this example. -
class A
-
{
-
void test(){}
-
}
-
class Main
-
{
-
A a;
-
a.test(); //Here it causes the Error, NullPointerException.
-
//Because here a is not initialized so a is null.
-
}
-
I think you understand my point.
Kind regards,
Dmjpro.
Thank you sir..,
Even though i declared.. it shows the same error.. plz say me exactly where i hav to declare....... and in wat type...
Thank you sir..,
Even though i declared.. it shows the same error.. plz say me exactly where i hav to declare....... and in wat type...
*initialize* using the new keyword.
Thank you sir..,
Even though i declared.. it shows the same error.. plz say me exactly where i hav to declare....... and in wat type...
Hi,
Can you show us how you have declared .. I think you have not done it correctly ..... I vil suggest you to check the previous posts again .. try to understand what those people are saying.
i don't know wheather it is right... or wrong..
[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; Customerdetails cud;
String s1,s2,s3,s4,s5, s6,s7;
or i hav to declare some where else..
say me...,
i don't know wheather it is right... or wrong..
[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; Customerdetails cud;
String s1,s2,s3,s4,s5, s6,s7;
or i hav to declare some where else..
say me...,
Hi,
You have not understood the previous posts. Here you are creating only instances not intializing them. So initialize ur all these instances in ur constructor and ur problem will be solved like .. -
cud = new Customerdetails();
-
save is null at that point. - Button save = new Button("Save");
Here, save holds a reference to an instance of the Button class which is not null.
Nepomuk 3,112
Recognized Expert Specialist
i don't know wheather it is right... or wrong..
[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; Customerdetails cud;
String s1,s2,s3,s4,s5, s6,s7;
or i hav to declare some where else..
say me...,
One (the?) Problem is somewhere else: -
super("SPlanting ");
-
setSize(800,800);
-
setLayout(new GridLayout(7,2,45,45));
-
l1=new Label("Date");
-
l2=new Label("Noofmixes");
-
l3=new Label("TotalBentomikused");
-
l4=new Label("TotalLusformused");
-
l5=new Label("starttime");
-
l6=new Label("Offtime");
-
l7=new Label("PowerConsumed");
-
l8=new Label("Opertorname");
-
-
-
add(l1);
-
add(date);
-
add(l2);
-
add(nom);
-
add(l3);
-
add(tb);
-
add(l4);
-
add(tl);
-
add(l5);
-
add(st);
-
add(l6);
-
add(ft);
-
add(l7);
-
add(pc);
-
add(l8);
-
add(on);
-
You never initialized "date".
Greetings,
Nepomuk
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