App.java

package com.iluwatar;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 
 * In Inventory we store the items with a given size. However, we do not store
 * more items than the inventory size. To address concurrent access problems we
 * use double checked locking to add item to inventory. In this method, the
 * thread which gets the lock first adds the item.
 */
public class App {

	public static void main(String[] args) {
		final Inventory inventory = new Inventory(1000);
		ExecutorService executorService = Executors.newFixedThreadPool(3);
		for (int i = 0; i < 3; i++) {
			executorService.execute(new Runnable() {
				@Override
				public void run() {
					while (inventory.addItem(new Item()))
						;
				}
			});
		}
	}
}