Modify the following Shelf class so it becomes a Generic class where String class can be replaced with any class.

Public class Shelf{

private String[] items;

private int capacity, itemsNumber = 0;

private String mainItem;

public Shelf(int capacity){

items = (String[]) new String [capacity];

}

public void add (String item){

if (!item.equals(mainItem))

items[itemsNumber++] = item;

}

public String getFirst() {return items[0];}

public int getCapcity() {return capacity;}

}