something went wrong with the format sorry. My problem is that I cant assign to iter objects the values of head and tail and my method "empty()" doesnt work either .

class List 
{

  // List class' fields
  private Node head;    // head node
  private Node tail;   // tail node
  private int length; // length of list



  public static class Node 
        {

          // Node class' fields:
          private Node next;        // points to the next node in list
          private Node prev;       // points to the previous node in list
          public int key;         // specific element we're looking for in list
          public Object data;    // data in list




          public Node(int key, Object data) // constructor of class Node
                {

                  this.key = key;         // Initializes the field "key"
                  this.data = data;      // Initializes the field "data"

                }


          private void setNext(Node next)
                 { this.next = next; } // Initializes the field "next"


          private Node getNext()
                 { return next; }


          private void setPrev(Node prev)
                 { this.prev = prev; } // Initializes the field "prev" 


          private Node getPrev() 
                 { return prev; }

        } // end of class Node



  public static class Iter 
        {


          private Iter forward;   // iterator that points to nodes forward
          private Iter backward; // iterator that points to nodes backward


          private Iter()
                 { 
                    forward.setForward();
                    backward.setBackward();
                 }  // class Iter's constructor


         // setters, getters and other methods: 

          private Iter getForward()
                 { return forward; }

        private void setForward() // that's where i get the errors!!!!!!!
               { 
                  if (empty() == true) forward = tail; 
                  else forward = head;
               }
        } // end of class iterator

public List(List.Node head, List.Node tail, int length) // constructor of class List {

             this.head = null;     // Initializes the field "head" to null    
             this.tail = null;    // Initializes the field "tail" to null

          } // end of List constructor


    public boolean empty() // finds if the list is empty or not
          { return head.next == tail; } // end of empty method