} finally {
        add(newCloseables, directExecutor());
      }
    }

    @Override
    public void close() {
      if (closed) {
        return;
      }
      synchronized (this) {
        if (closed) {
          return;
        }
        closed = true;
      }
      for (Map.Entry<AutoCloseable, Executor> entry : entrySet()) {

   * {@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
   */

 * methods for more details.
 *
 * <p>Note that this implementation is not synchronized. If multiple threads access the same cell of
 * an {@code ArrayTable} concurrently and one of the threads modifies its value, there is no
 * guarantee that the new value will be fully visible to the other threads. To guarantee that
 * modifications are visible, synchronize access to the table. Unlike other {@code Table}

   * safe to do so. The exact circumstances under which a copy will or will not be performed are
   * undocumented and subject to change.
   *
   * <p>This method is safe to use even when {@code sortedMultiset} is a synchronized or concurrent
   * collection that is currently being modified by another thread.
   *
   * @throws NullPointerException if {@code sortedMultiset} or any of its elements is null
   */

   * {@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
   */

            this.supplier = supplier;
        }

        @Override
        public Set<Entry<K, V>> entrySet() {
            if (delegate == null) {
                synchronized (this) {
                    if (delegate == null) {
                        delegate = supplier.get();
                    }
                }
            }
            return delegate.entrySet();

   * safe to do so. The exact circumstances under which a copy will or will not be performed are
   * undocumented and subject to change.
   *
   * <p>This method is safe to use even when {@code sortedMultiset} is a synchronized or concurrent
   * collection that is currently being modified by another thread.
   *
   * @throws NullPointerException if {@code sortedMultiset} or any of its elements is null
   */

new APIs so we can get out of alpha.

 *  New: Support Java 21's virtual threads (‘OpenJDK Project Loom’). We changed OkHttp's internals
    to use `Lock` and `Condition` instead of `synchronized` for best resource utilization.

 *  New: Switch our Internationalized Domain Name (IDN) implementation to [UTS #46 Nontransitional

    assertEquals("null=null", e.toString());
    assertEquals(0, e.hashCode());
  }

  /** See {@link SynchronizedBiMapTest} for more tests. */
  @J2ktIncompatible // Synchronized
  public void testSynchronizedBiMap() {
    BiMap<String, Integer> bimap = HashBiMap.create();
    bimap.put("one", 1);
    BiMap<String, Integer> sync = Maps.synchronizedBiMap(bimap);
    bimap.put("two", 2);

        postWriteCleanup();
      }

      if (createNewEntry) {
        try {
          // Synchronizes on the entry to allow failing fast when a recursive load is
          // detected. This may be circumvented when an entry is copied, but will fail fast most
          // of the time.
          synchronized (e) {
            return loadSync(key, hash, loadingValueReference, loader);
          }
        } finally {