Example Java Container Class

import java.util.ArrayList;
import java.util.List;

class ProductList {
    List<Product> products;

    ProductList()
    {
        products = new ArrayList<Product>();
    }
    void add(Product p)
    {
        products.add(p);
    }
    void set(int index, Product p)
    {
        products.set(index, p);
    }
    void clear()
    {
        products.clear();
    }
    void remove(int index)
    {
        products.remove(index);
    }
    void remove(Product p)
    {
        products.remove(p);
    }
    Product get(int index)
    {
        return (Product)products.get(index);
    }
    int getTotalInventory()
    {
        int inventory = 0;
        for(int i = 0; i < products.size(); i++) {
            Product pp = products.get(i);
            if(pp != null) {
                inventory += pp.getInventory();
            }
        }
        return inventory;
    }
}