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 =

            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);

            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);

    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:

        final int[] callCount = { 0 };

        SearchLogHelper mockSearchLogHelper = new SearchLogHelper() {
            @Override
            public void storeSearchLog() {
                synchronized (lock) {
                    callCount[0]++;
                    if (callCount[0] % 2 == 0) {
                        throw new RuntimeException("Even call error");
                    }

  static class Key {
    private final int value;
    private WeakReference<String> toString;

    Key(int value) {
      this.value = value;
    }

    @Override
    public synchronized String toString() {
      String s;
      if (toString != null) {
        s = toString.get();
        if (s != null) {
          return s;
        }
      }
      s = Integer.toString(value);

 *   // do other things since the monitor was not available
 * }
 * }
 *
 * <h2>Comparison with {@code synchronized} and {@code ReentrantLock}</h2>
 *
 * <p>The following examples show a simple threadsafe holder expressed using {@code synchronized},
 * {@link ReentrantLock}, and {@code Monitor}.
 *
 * <h3>{@code synchronized}</h3>
 *
 * <p>This version is the fewest lines of code, largely because the synchronization mechanism used

                this.uhe = uhe;
            } catch (final Exception ex) {
                this.uhe = new UnknownHostException(ex.getMessage());
            } finally {
                synchronized (sem) {
                    sem.count--;
                    sem.notify();
                }
            }
        }
    }

                synchronized (result) {
                    result.addMissingArtifact(artifact);
                }
            } catch (ArtifactResolutionException e) {
                // This is really a wagon TransferFailedException so something went wrong after we successfully
                // retrieved the metadata.

                synchronized (result) {

        }
    }

    public void test_evaluate_concurrency() {
        queryRescorer = new QueryRescorer() {
            private int callCount = 0;

            @Override
            public synchronized RescorerBuilder<?> evaluate(Map<String, Object> params) {
                callCount++;
                if (callCount % 2 == 0) {
                    return createMockRescorerBuilder();
                }