Need the following java program completed:

 

import java.util.ArrayList;

 

/**

 * Manage the stock in a business.

 * The stock is described by zero or more Products.

 * 

 * @author (your name) 

 * @version (a version number or a date)

 */

public class StockManager

{

  // A list of the products.

  private ArrayList<Product> stock;

 

  /**

   * Initialise the stock manager.

   */

  public StockManager()

  {

    stock = new ArrayList<>();

  }

 

  /**

   * Add a product to the list.

   * @param item The item to be added.

   */

  public void addProduct(Product item)

  {

    stock.add(item);

  }

   

  /**

   * Receive a delivery of a particular product.

   * Increase the quantity of the product by the given amount.

   * @param id The ID of the product.

   * @param amount The amount to increase the quantity by.

   */

  public void delivery(int id, int amount)

  {

  }

   

  /**

   * Try to find a product in the stock with the given id.

   * @return The identified product, or null if there is none

   *    with a matching ID.

   */

  public Product findProduct(int id)

  {

    return null;

  }

   

  /**

   * Locate a product with the given ID, and return how

   * many of this item are in stock. If the ID does not

   * match any product, return zero.

   * @param id The ID of the product.

   * @return The quantity of the given product in stock.

   */

  public int numberInStock(int id)

  {

    return 0;

  }

 

  /**

   * Print details of all the products.

   */

  public void printProductDetails()

  {

  }

}