import java.util.Collection;
import java.util.Set;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * {@link Set} implementation that asserts that a given lock is held whenever one of its methods is
 * called.
 */
@NullUnmarked
class LockHeldAssertingSet<E> extends ForwardingSet<E> implements Serializable {
  final Set<E> delegate;
  final Object mutex;

        // We can test the public fields that are set.
        assertEquals(200, dfsRootEnum.level, "The level should be initialized to 200.");
        assertNotNull(dfsRootEnum.info, "The info struct should not be null.");
        assertEquals(200, dfsRootEnum.info.level, "The info.level should be set to the same value as level.");

* Set the `Cache-Control: no-cache` header to **prevent caching** of the stream.
* Set a special header `X-Accel-Buffering: no` to **prevent buffering** in some proxies like Nginx.

  // & this future completes. Released when the future releases the reference to the running state
  private @Nullable Set<Throwable> seenExceptions = null;
  private int remaining;

  AggregateFutureState(int remainingFutures) {
    this.remaining = remainingFutures;
  }

  final Set<Throwable> getOrInitSeenExceptions() {
    if (seenExceptions == null) {
      seenExceptions = newHashSet();

      public <E extends Comparable<E>> Set<E> create(Collection<E> contents) {
        return new TreeSet<E>(contents);
      }
    },
    UnmodifiableSetImpl {
      @Override
      public <E extends Comparable<E>> Set<E> create(Collection<E> contents) {
        return unmodifiableSet(new HashSet<E>(contents));
      }
    },
    SynchronizedSetImpl {
      @Override
      public <E extends Comparable<E>> Set<E> create(Collection<E> contents) {

import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.stream.Collectors;

import static java.util.Comparator.reverseOrder;

/**
 * This class ensures that the release notes index page has the appropriate anchors and include directives
 * for the current repository version.
 */
public class ReleaseNotesIndexGenerator {

        inCompletionOrder(
            ImmutableList.<ListenableFuture<Long>>of(future1, future2, future3, future4, future5));
    future2.set(1L);
    future5.set(2L);
    future1.set(3L);
    future3.set(4L);
    future4.set(5L);

    long expectedResult = 1L;
    for (ListenableFuture<Long> future : futures) {
      assertEquals((Long) expectedResult, getDone(future));

        inCompletionOrder(
            ImmutableList.<ListenableFuture<Long>>of(future1, future2, future3, future4, future5));
    future2.set(1L);
    future5.set(2L);
    future1.set(3L);
    future3.set(4L);
    future4.set(5L);

    long expectedResult = 1L;
    for (ListenableFuture<Long> future : futures) {
      assertEquals((Long) expectedResult, getDone(future));

                      }

                      @Override
                      public Set<Entry<String>> entrySet() {
                        Set<Entry<String>> backingSet = super.entrySet();
                        return new ForwardingSet<Entry<String>>() {
                          @Override
                          protected Set<Entry<String>> delegate() {
                            return backingSet;
                          }

  final Set<E> delegate;
  final Object mutex;

  LockHeldAssertingSet(Set<E> delegate, Object mutex) {
    checkNotNull(mutex);
    this.delegate = delegate;
    this.mutex = mutex;
  }

  @Override
  protected Set<E> delegate() {
    return delegate;
  }

  @Override
  public String toString() {
    assertTrue(Thread.holdsLock(mutex));