Above each method can be found the sentence about what the method should do. Please use Linked Lists, and double linked lists. Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not

public int indexOf(Object o) { return 0; } 

Removes all of the elements from this list. The list will be empty after this call returns.

public void clear() { }

Appends the specified element to the end of this list.

public boolean add(E e) { return false; }

Removes the first occurrence of the specified element from this list, if it is present. If this list does not * contain the element, it is unchanged. Returns {@code true} if this list contained the specified element.

public boolean remove(Object o) { return false; }