* {@code ImmutableList.of(list)} returns an {@code ImmutableList<List<String>>} containing one
   * element (the given list itself).
   *
   * <p>This method is safe to use even when {@code elements} is a synchronized or concurrent
   * collection that is currently being modified by another thread.
   *
   * @throws NullPointerException if {@code elements} contains a null element
   */

    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see
    https://groups.google.com/g/google-web-toolkit-contributors/c/CqYH59Dt_rQ/m/uVGW1QdUsXUJ
    for details.

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one

import java.util.Collections;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

### Рівночасні бургери { #concurrent-burgers }

Ви йдете зі своєю симпатією по фастфуд, стаєте в чергу, доки касир приймає замовлення у людей перед вами. 😍

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

Потім ваша черга, ви замовляєте 2 дуже вишукані бургери для вашої симпатії і для себе. 🍔🍔

import com.google.common.testing.NullPointerTester;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CountDownLatch;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * @author Charles Fry
 */
@GwtCompatible
@J2ktIncompatible // MapMaker
@NullUnmarked

import java.util.UUID;
import java.util.concurrent.BlockingDeque;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.LinkedBlockingDeque;

 * the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.util.concurrent.MoreExecutors.newThread;
import static com.google.common.util.concurrent.MoreExecutors.renamingDecorator;
import static com.google.common.util.concurrent.Platform.restoreInterruptIfIsInterruptedException;

import com.google.common.annotations.GwtIncompatible;

 * the License.
 */

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

/** Forwarding wrapper around a {@code Lock}. */
@J2ktIncompatible
@GwtIncompatible

 * method equivalent to {@link java.util.concurrent.locks.ReentrantLock#hasQueuedThread(Thread)}. If
 * the {@link #callAndAssertWaits} method is ever called in a test, the lock-like object must have a
 * method equivalent to {@link
 * java.util.concurrent.locks.ReentrantLock#hasWaiters(java.util.concurrent.locks.Condition)},

import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.CancellationException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;