Implementing a String collection class - open to bidding

In this mini-project you have to build a class which implements an interface called WordStore. This interface defines a collection which stores Strings. It has methods: public void add(String word) Adds a String to the collection public int count(String word) Returns the number of times a String is in the collection public void remove(String word) Removes one occurrence of a String from the collection, or leaves the collection unchanged if the String does not occur in it. in the most effiecent way. making use of hash table, double hashing etc. the fast and most efficient way.