Strange nullPointer ?

Hi there!

Im new to this forum, so I dont know if i'm doing this correctly.

I've searcher the forum, but couldnt find this problem (probably not the right search-words :P)

This is my code

import java.awt.*;

import java.awt.event.*;

import java.util.*;

import java.io.*;

//class

public class database implements Serializable{

private LinkedList users = new LinkedList();

private ListIterator iterator = users.listIterator();

//Constructor

public database(){

}

public void addUser(user giveUser){

try {ObjectInputStream in = new ObjectInputStream(new FileInputStream("database.dat"));

users=(LinkedList)in.readObject();

in.close();

System.out.println("Laden succesvol");

}

catch(Exception p) {

System.out.println("It wont work");

}

users.add(giveUser); //this gives me a nullPointer exeption

System.out.println(""+giveUser); //this doesnt give me a nullpointer exeption and just prints the user on the screen

try {ObjectOutputStream uit = new ObjectOutputStream(new FileOutputStream("database.dat"));

uit.writeObject(users);

uit.flush();

uit.close();

System.out.println("Opslaan Succesvol");

}

catch(IOException p) {

System.out.println("Hij doet het niet");

}

}

}

I dont know why i'm getting the Nullpointer at line 26 (added the comment to it)

Note that "user" is a self-made class.... I beleve there's a standard one... dunno about that though... but whatever :-) Just so you know.

can anyone help me?

thanks in advance

[1670 byte] By [Qternocq_a] at [2007-10-2 9:55:19]