Null Pointer Exception

[ScKaSx]

Hi All,

I am working on a code for linked lists and am encountering a strange null pointer exception error that I don't understand in the following code:

public class Node
{
	public Comparable item;
	public Node next;

	public Node(Comparable i)
	{
		item = i;
		next = null;
	}
}

private Node head;
private Node iterator;

public MySortedLinkedList()
{ 
	head = null; 
	iterator = null;
}
	
public void add(Comparable item)
{
        if (iterator == null) {
                 [B]head.item = item;[/B]
        }
}

I have test code that loads the linked list and when it tries to 'add' an element to the array the program stops on the bold statement, where I am trying to change the value of the head.item location to something other than null. Why do I get an exception here?

Cheers,
ScKaSx

[ScKaSx]

Hi All,

For anyone that is curious about this, I found the solution. I thought I initialized the Node head when I wrote:

head = null;

however, this did not create a new node. Therefore the correction for the bold statement would be:

head = new Node(item);

How come coding can't always be intuitive?

Cheers,
ScKaSx