// If NoWait is set, Get() will return the last good value,
	// if TTL has expired but 2x TTL has not yet passed,
	// but will fetch a new value in the background.
	NoWait bool
}

// Cache contains a synchronized value that is considered valid
// for a specific amount of time.
// An Update function must be set to provide an updated value when needed.
type Cache[T any] struct {
	// updateFn must return an updated value.

import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link Synchronized#deque} and {@link Queues#synchronizedDeque}.
 *
 * @author Kurt Alfred Kluever
 */
@NullUnmarked
public class SynchronizedDequeTest extends TestCase {

  protected Deque<String> create() {
    TestDeque<String> inner = new TestDeque<>();
    Deque<String> outer = Synchronized.deque(inner, inner.mutex);

    assertTrue(Thread.holdsLock(mutex));
    return super.isEmpty();
  }

  /*
   * We don't assert that the lock is held during calls to iterator(), stream(), and spliterator:
   * `Synchronized` doesn't guarantee that it will hold the mutex for those calls because callers
   * are responsible for taking the mutex themselves:

        }
        buffer.setLength(buffer.length() - ", ".length());
        return new String(buffer);
    }

    /**
     * Initializes the class.
     */
    protected static synchronized void initialize() {
        if (!initialized) {
            DisposableUtil.add(() -> {
                ResourceBundle.clearCache();
                initialized = false;
            });

        StringBuilder buffer = new StringBuilder(128);
        buffer.append("Progress (").append(transfers.size()).append("): ");

        synchronized (transfers) {
            Iterator<TransferResourceAndSize> entries = transfers.values().iterator();
            while (entries.hasNext()) {
                TransferResourceAndSize entry = entries.next();

   * @return a synchronized view of the specified navigable set.
   * @since 13.0
   */
  @GwtIncompatible // NavigableSet
  @J2ktIncompatible // Synchronized
  public static <E extends @Nullable Object> NavigableSet<E> synchronizedNavigableSet(
      NavigableSet<E> navigableSet) {
    return Synchronized.navigableSet(navigableSet);
  }

 * strategies.
 *
 * <ul>
 *   <li>SafeAtomicHelper: uses Atomic FieldsUpdaters to implement synchronization
 *   <li>SynchronizedHelper: uses {@code synchronized} blocks for synchronization
 * </ul>
 *
 * To force selection of our fallback strategies we load {@link AggregateFutureState} (and all of

  if (position.index == length) {
    // STANDARD_DATE_FORMAT must match exactly; all text must be consumed, e.g. no ignored
    // non-standard trailing "+01:00". Those cases are covered below.
    return result
  }
  synchronized(BROWSER_COMPATIBLE_DATE_FORMAT_STRINGS) {
    for (i in 0 until BROWSER_COMPATIBLE_DATE_FORMAT_STRINGS.size) {
      var format: DateFormat? = BROWSER_COMPATIBLE_DATE_FORMATS[i]
      if (format == null) {
        format =

    }
    enumConstantCache.put(enumClass, result);
    return result;
  }

  static <T extends Enum<T>> Map<String, WeakReference<? extends Enum<?>>> getEnumConstants(
      Class<T> enumClass) {
    synchronized (enumConstantCache) {
      Map<String, WeakReference<? extends Enum<?>>> constants = enumConstantCache.get(enumClass);
      if (constants == null) {
        constants = populateCache(enumClass);
      }

            if (name.startsWith(concurrentPackage)
                // Use other classloader for ListenableFuture, so that the objects can interact
                && !ListenableFuture.class.getName().equals(name)) {
              synchronized (loadedClasses) {
                Class<?> toReturn = loadedClasses.get(name);
                if (toReturn == null) {
                  toReturn = super.findClass(name);
                  loadedClasses.put(name, toReturn);