Hello, what is wrong with my add method? the bolded parts are not working

public class MyOrderedLinkedList extends MyAbstractList {

private Node head, tail;

/** * Create a default list */ public MyOrderedLinkedList() { }

/** * Create a list from an array of objects */ public MyOrderedLinkedList(E[] objects) { super(objects); }

// ************************************************************** // ************************************************************** /** * Add a new element to the list in order. */ // ************************************************************** // **************************************************************

public void add(E e) {

Node newNode = new Node(e);// Create a new node if (head == null || tail == null) { // the new node is the only node in list newNode.next = head; // link the new node with the head head = newNode; // head points to the new node if (tail == null) { tail = head; } } else if (e >= tail.element) { // new node is greater then tail tail.next = newNode; // Link the new with the last node tail = tail.next; // tail now points to the last node } else if (e <= head.element) { // new node is smaller then head newNode.next = head; // link the new node with the head head = newNode; // head points to the new node } else { Node current = head; for (int i = 1; i <= size; i++) { if (current.element >= e) { break; } current = current.next; } Node temp = current.next; current.next = new Node(e); (current.next).next = temp; } size++; // Increase size }

/** * Return the head element in the list */ public E getFirst() { if (size == 0) { return null; } else { return head.element; } }

/**Return the last element in the list*/ public E getLast() { if (size == 0) { return null; } else { return tail.element; } }

// ************************************************************** // ************************************************************** /**Must be rewritten to add a new element to the list in order.*/ // ************************************************************** // ************************************************************** public void addFirst(E e) { Node newNode = new Node(e); // Create a new node newNode.next = head; // link the new node with the head head = newNode; // head points to the new node size++; // Increase list size

if (tail == null) // the new node is the only node in list { tail = head; } }

// ************************************************************** // ************************************************************** /**Must be rewritten to add a new element to the list in order.*/ // ************************************************************** // ************************************************************** public void addLast(E e) { Node newNode = new Node(e); // Create a new for element e

if (tail == null) { head = tail = newNode; // The new node is the only node in list } else { tail.next = newNode; // Link the new with the last node tail = tail.next; // tail now points to the last node }

size++; // Increase size }

@Override // ************************************************************** // ************************************************************** /** * Must be rewritten to add a new element to the list in order. */ // ************************************************************** // ************************************************************** public void add(int index, E e) { if (index == 0) { addFirst(e); } else if (index >= size) { addLast(e); } else { Node current = head; for (int i = 1; i < index; i++) { current = current.next; } Node temp = current.next; current.next = new Node(e); (current.next).next = temp; size++; } }

// ************************************************************** // ************************************************************** /**Must be rewritten to do nothing and return null.*/ // ************************************************************** // ************************************************************** public E removeFirst() { if (size == 0) { return null; } else { Node temp = head; head = head.next; size--; if (head == null) { tail = null; } return temp.element; } }

// ************************************************************** // ************************************************************** /**Must be rewritten to do nothing and return null.*/ // ************************************************************** // ************************************************************** public E removeLast() { if (size == 0) { return null; } else if (size == 1) { Node temp = head; head = tail = null; size = 0; return temp.element; } else { Node current = head;

for (int i = 0; i < size - 2; i++) { current = current.next; }

Node temp = tail; tail = current; tail.next = null; size--; return temp.element; } }

@Override /** * Remove the element at the specified position in this list. Return the * element that was removed from the list. */ public E remove(int index) { if (index < 0 || index >= size) { return null; } else if (index == 0) { return removeFirst(); } else if (index == size - 1) { return removeLast(); } else { Node previous = head;

for (int i = 1; i < index; i++) { previous = previous.next; }

Node current = previous.next; previous.next = current.next; size--; return current.element; } }

@Override /** * Override toString() to return elements in the list */ public String toString() { StringBuilder result = new StringBuilder("[");

Node current = head; for (int i = 0; i < size; i++) { result.append(current.element); current = current.next; if (current != null) { result.append(", "); // Separate two elements with a comma } else { result.append("]"); // Insert the closing ] in the string } }

return result.toString(); }

@Override /** * Clear the list */ public void clear() { size = 0; head = tail = null; }

@Override /** * Return true if this list contains the element e */ public boolean contains(E e) { if (size == 0) { return false; } else { Node current = head;

while (current != null) { if (current.element == e) { return true; } current = current.next; } } return false; }

@Override /** * Return the element at the specified index */ public E get(int index) { if (index < 0 || index >= size) { return null; // Out of range } else if (index == 0) { return getFirst(); } else if (index == size - 1) { return getLast(); } else { Node current = head.next;

for (int i = 1; i < index; i++) { current = current.next; } return current.element; } }

@Override /** * Return the index of the head matching element in this list. Return -1 * if no match. */ public int indexOf(E e) { if (head.element == e) { return 0; } else if (tail.element == e) { return size - 1; } else { Node current = head.next; int index = 1; while (current != null) { if (current.element == e) { return index; } current = current.next; index++; } } return -1; }

@Override /** * Return the index of the last matching element in this list. Return -1 * if no match. */ public int lastIndexOf(E e) { int index = -1; Node current = head; for (int i = 0; i < size; i++) { if (current.element == e) { index = i; } current = current.next; }

return index; }

@Override /** * Replace the element at the specified position in this list with the * specified element. */ public E set(int index, E e) { if (index < 0 || index > size - 1) { return null; } else { Node current = head; for (int i = 0; i < index; i++) { current = current.next; }

current.element = e; return current.element; } }

@Override /** * Override iterator() defined in Iterable */ public java.util.Iterator iterator() { return new LinkedListIterator(); }

private void checkIndex(int index) { if (index < 0 || index >= size) { throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);

} }

private class LinkedListIterator implements java.util.Iterator {

private Node current = head;// Current index private Node previous = null; private Node previous2 = null; private boolean removeCalled = false;

@Override public boolean hasNext() { return (current != null); }

@Override public E next() { E e = current.element; previous2 = previous; previous = current; current = current.next; removeCalled = false; return e; }

@Override public void remove() {

} } // end of LinkedListIterator

private static class Node {

E element; Node next;

public Node(E element) { this.element = element; } } // end of Node }