Sorted Double Linked List.

Question

public class DLinkedList {
class Node {
String data;
Node next = null;
Node prev = null;
public Node(String o, Node n, Node p){
data = o;
next = n;
prev = p;
private int max;
private Node head;
private Node current = null;
public DLinkedList(int max_size) {
head = null;
current = null;
max = max_size;
public boolean isEmpty() {
public void insert(String o) {
Node n;
while (current != null && o.compareToIgnoreCase(current.data) > 0)
current.prev = current;
current = current.next;
if (current.prev == null)
// First Item in List
n = new Node(o, current, null);
else
current.prev.next = new Node(o, current, current.prev);
I am working on the insert and keep getting a null pointer exception. Can someone point me in the right direction.
Thanks

Answer 1

if (current.prev == null)
  // First Item in List
  n = new Node(o, current, null);
}This code right here will cause a NullPointerException if current is still null, which is one of the possible exit conditions in your loop.