private ReentrantLock lockA;
  private ReentrantLock lockB;
  private ReentrantLock lockC;
  private ReentrantReadWriteLock.ReadLock readLockA;
  private ReentrantReadWriteLock.ReadLock readLockB;
  private ReentrantReadWriteLock.ReadLock readLockC;
  private ReentrantReadWriteLock.WriteLock writeLockA;
  private ReentrantReadWriteLock.WriteLock writeLockB;
  private ReentrantReadWriteLock.WriteLock writeLockC;

      super(fair);
      this.readLock = new CycleDetectingReentrantReadLock(this);
      this.writeLock = new CycleDetectingReentrantWriteLock(this);
      this.lockGraphNode = Preconditions.checkNotNull(lockGraphNode);
    }

    ///// Overridden ReentrantReadWriteLock methods. /////

    @Override
    public ReadLock readLock() {
      return readLock;
    }

    @Override

    Object key = new Object();
    Lock readLock = striped.get(key).readLock();
    WeakReference<Object> garbage = new WeakReference<>(new Object());
    GcFinalization.awaitClear(garbage);
    Lock writeLock = striped.get(key).writeLock();
    readLock.lock();
    assertFalse(writeLock.tryLock());
    readLock.unlock();
  }

  private ReentrantLock lockA;
  private ReentrantLock lockB;
  private ReentrantLock lockC;
  private ReentrantReadWriteLock.ReadLock readLockA;
  private ReentrantReadWriteLock.ReadLock readLockB;
  private ReentrantReadWriteLock.ReadLock readLockC;
  private ReentrantReadWriteLock.WriteLock writeLockA;
  private ReentrantReadWriteLock.WriteLock writeLockB;
  private ReentrantReadWriteLock.WriteLock writeLockC;

    Object key = new Object();
    Lock readLock = striped.get(key).readLock();
    WeakReference<Object> garbage = new WeakReference<>(new Object());
    GcFinalization.awaitClear(garbage);
    Lock writeLock = striped.get(key).writeLock();
    readLock.lock();
    assertFalse(writeLock.tryLock());
    readLock.unlock();
  }

    private final ReadWriteLock delegate;

    WeakSafeReadWriteLock() {
      this.delegate = new ReentrantReadWriteLock();
    }

    @Override
    public Lock readLock() {
      return new WeakSafeLock(delegate.readLock(), this);
    }

    @Override
    public Lock writeLock() {
      return new WeakSafeLock(delegate.writeLock(), this);
    }
  }

   * This covers a bug where if a listener was installed that would stop the manager if any service
   * fails and something failed during startup before service.start was called on all the services,
   * then awaitStopped would deadlock due to an IllegalStateException that was thrown when trying to
   * stop the timer(!).
   */
  public void testFailStart_stopOthers() throws TimeoutException {
    Service a = new FailStartService();

   * under {@code directExecutor}: Not only might the wait for a lock be long, but if the running
   * thread was holding a lock, the listener may deadlock or break lock isolation.
   *
   * <p>This instance is equivalent to:
   *
   * <pre>{@code
   * final class DirectExecutor implements Executor {
   *   public void execute(Runnable r) {
   *     r.run();

    Thread.sleep(UNIT.toMillis(3 * DELAY));
    assertEquals(1, service.numIterations.get());
  }

  public void testCustomScheduler_deadlock() throws InterruptedException, BrokenBarrierException {
    final CyclicBarrier inGetNextSchedule = new CyclicBarrier(2);
    // This will flakily deadlock, so run it multiple times to increase the flake likelihood
    for (int i = 0; i < 1000; i++) {
      Service service =

import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

public final class InterruptibleTaskTest extends TestCase {

  // Regression test for a deadlock where a task could be stuck busy waiting for the task to
  // transition to DONE
  public void testInterruptThrows() throws Exception {
    final CountDownLatch isInterruptibleRegistered = new CountDownLatch(1);