Le serveur 💁 dit quelque chose à son collègue dans la cuisine 👨‍🍳 pour qu'il sache qu'il doit préparer vos burgers 🍔 (bien qu'il soit déjà en train de préparer ceux des clients précédents).

<img src="/img/async/concurrent-burgers/concurrent-burgers-03.png" class="illustration">

Vous payez 💸.

Le serveur 💁 vous donne le numéro assigné à votre commande.

### Concurrent Burgers { #concurrent-burgers }

You go with your crush to get fast food, you stand in line while the cashier takes the orders from the people in front of you. 😍

<img src="/img/async/concurrent-burgers/concurrent-burgers-01.png" class="illustration">

Then it's your turn, you place your order of 2 very fancy burgers for your crush and you. 🍔🍔

import java.util.List;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicReferenceArray;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

<img src="/img/async/concurrent-burgers/concurrent-burgers-02.png" class="illustration">

El cajero dice algo al cocinero en la cocina para que sepan que tienen que preparar tus hamburguesas (aunque actualmente están preparando las de los clientes anteriores).

<img src="/img/async/concurrent-burgers/concurrent-burgers-03.png" class="illustration">

Pagas. 💸

El cajero te da el número de tu turno.

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.mockito.Mockito;

import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.locks.ReentrantLock;

    // Use concurrent queue for lock-free operations
    private static final java.util.concurrent.ConcurrentLinkedQueue<byte[]> bufferQueue =
            new java.util.concurrent.ConcurrentLinkedQueue<>();

    // Track queue size with atomic counter for efficiency
    private static final java.util.concurrent.atomic.AtomicInteger queueSize = new java.util.concurrent.atomic.AtomicInteger(0);

    /**

import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.locks.ReentrantLock;

- **Logging Abstraction** (`org.codelibs.core.log`) - Flexible logging system supporting JCL (Jakarta Commons Logging) and JUL (Java Util Logging)
- **Concurrent Utilities** (`org.codelibs.core.concurrent`) - Thread-safe collections and concurrency helpers using modern concurrent APIs
- **Crypto & Security** (`org.codelibs.core.crypto`, `org.codelibs.core.security`) - Basic cryptographic utilities, message digest operations, and secure random generation

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.LongBinaryOperator;
import java.util.function.LongUnaryOperator;
import org.jspecify.annotations.Nullable;

/**
 * A map containing {@code long} values that can be atomically updated. While writes to a