Note: Above each method can be found the sentence about what the method should do. Please use Linked Lists, and double linked lists. Returns an array containing all of the elements in this list in proper sequence (from first to last element).

public Object[] toArray() { return new Object[0]; }

Removes the element at the specified position in this list. Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the list.

public E remove(int index) { return null; }

Inserts the specified element at the specified position in this list. Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).

public void add(int index, E element) { }