}
      }
    } finally {
      if (interrupted) {
        Thread.currentThread().interrupt();
      }
    }
  }

  /**
   * Invokes {@code lock.}{@link Lock#tryLock(long, TimeUnit) tryLock(timeout, unit)}
   * uninterruptibly.
   *
   * @since 33.4.0 (but since 30.0 in the JRE flavor)
   */
  @J2ktIncompatible
  @GwtIncompatible // concurrency

</p>

<p class="rule">
A successful call to <code>l.TryLock</code> (or <code>l.TryRLock</code>)
is equivalent to a call to <code>l.Lock</code> (or <code>l.RLock</code>).
An unsuccessful call has no synchronizing effect at all.
As far as the memory model is concerned,
<code>l.TryLock</code> (or <code>l.TryRLock</code>)
may be considered to be able to return false

    }

    // reference queues, for garbage collection cleanup

    /** Cleanup collected entries when the lock is available. */
    void tryDrainReferenceQueues() {
      if (tryLock()) {
        try {
          maybeDrainReferenceQueues();
        } finally {
          unlock();
        }
      }
    }

    @GuardedBy("this")