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())) ; } }); } } }