Win a copy of Re-engineering Legacy Software this week in the Refactoring forum
or Docker in Action in the Cloud/Virtualization forum!
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

:( simple chat client n server..

 
simranjit singh
Greenhorn
Posts: 12
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
i am developing a code from headfirst java book from orielly on netbeans..

since d code is huge i cannot type it or copy it here.. so i hv uploaded it on d site..

megaupload
try compiling server.java, login.java, client.java
and running server.java n login.java
d problem i am having is when i try sending message from client d printwriter or my textfiled gives a nullpointer exception.. i hv tried a lot debugging to find wat might b probling but cannot find it..
i will b glad if somebody spends his/her time telling wat d prob is.. i m kinda newbie for java..

netbeans m using is 5.5 n jdk1.6
 
Deepak Bala
Bartender
Posts: 6663
5
Firefox Browser Linux MyEclipse IDE
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
What is "b" "d" "m" "n" "wat" ? Please use real words. Also please post your stack trace and give us a better high level overview of your problem to receive better responses
 
Jesper de Jong
Java Cowboy
Saloon Keeper
Posts: 15207
36
Android IntelliJ IDE Java Scala Spring
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Where do you see the NullPointerException? Look carefully at the error message and the stack trace. It will tell you exactly in which line of code in which source file the exception happens.

Lookup that line in your source code. Something there is null when it shouldn't be. Find out why that is so and solve the problem.
 
simranjit singh
Greenhorn
Posts: 12
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
java.lang.NullPointerException
at chat.Client.jButton1ActionPerformed(Client.java:131)
at chat.Client.access$000(Client.java:20)
at chat.Client$1.actionPerformed(Client.java:73)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:6038)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3260)
at java.awt.Component.processEvent(Component.java:5803)
at java.awt.Container.processEvent(Container.java:2058)
at java.awt.Component.dispatchEventImpl(Component.java:4410)
at java.awt.Container.dispatchEventImpl(Container.java:2116)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)
at java.awt.Container.dispatchEventImpl(Container.java:2102)
at java.awt.Window.dispatchEventImpl(Window.java:2429)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)
 
simranjit singh
Greenhorn
Posts: 12
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
this above is the stack trace as requested..
the problem is the code for the jtextfield is all self generated by netbeans ide and i am not able to find out why it is showing me nullpointer
 
Ernest Friedman-Hill
author and iconoclast
Marshal
Pie
Posts: 24208
35
Chrome Eclipse IDE Mac OS X
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
According to the stack trace it's happening in Client.java at line 131. Something on the left hand side of a dot or a "[" is null. Whatever fits this description on this line must be null, so find out why it is.
 
simranjit singh
Greenhorn
Posts: 12
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
this i also know..
if i wz able to find the error, why wud i post it here..
i dont know why is it giving error, according to me code is fine..

[ March 02, 2007: Message edited by: simranjit singh ]

[Andrew: removed swearing.]
[ March 02, 2007: Message edited by: Andrew Monkhouse ]
 
Henry Wong
author
Marshal
Pie
Posts: 20892
75
C++ Chrome Eclipse IDE Firefox Browser Java jQuery Linux VI Editor Windows
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Originally posted by simranjit singh:
this i also know..
if i wz able to find the error, why wud i post it here..
i dont know why is it giving error, according to me code is fine..


What do you mean by "according to me code is fine"? What did you look at?

Bring up netbeans, load up client.java, and go to line 131. At this point, either...

(1) bring up the netbeans debugger, place a breakpoint just before line 131. run it to the breakpoint. and trace it til you get the exception. or...

(2) place a System.out.print() just before and after where the error is happening, printing out variables being used. After a couple of runs, you should be able to isolate the exact line and variable causing it.


Don't assume that you found the error... if you don't know why it is happening, you haven't found the error.

Henry
 
fred rosenberger
lowercase baba
Bartender
Posts: 12086
29
Chrome Java Linux
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
according to me code is fine

Well, if according to YOU it's fine, then why are we having this discussion?

OH, that's right. Because your code is NOT fine. That is what the exception is telling you.

if i wz able to find the error, why wud i post it here..


I'm not sure what all these terms mean... "wz" is not a word, nor is "wud". But if you mean what i THINK you mean, the answer is to get help. To learn. to get guidance.

If you think we are here to do you work for you, you are wrong. We try and teach people how to solve their problems, and how to think about things.

Both Henry and Ernest have give you suggestions on where to start. Follow their advice, and if you get stuck, come back with what you have found, and ask a new question.
 
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic