Provide the specification for the List ADT on the List interface. For this you will have to describe the pre- and pos-conditions for the remaining methods. You may use english in your descriptions, though you may want to consider using Java boolean expressions to make the specifications clearer and unambiguous. Make sure to write the specs as Javadoc comments.

Extend the List interface with the following methods:

Object[] toArray(): returns an array with all the elements in the list.

String toString(): generates a string representation of the list that has the following format: (key,item) -- (key,item) -- (key,item) -- ...

Implement all the methods in every list class.

public interface List,V> {
  
   public abstract boolean add(K key,V value);
  
   public abstract V remove(K key);
  
   public abstract V remove(int n);
  
   public abstract V remove();
  
   public abstract V lookup(K key);
  
   public abstract int size();
  
   public abstract V get(int n);