assertThat(sepStopwatchA.get()).isNotNull();
    // Clear all references to the Stopwatch and wait for it to be gc'd.
    sepStopwatchA.set(null);
    GcFinalization.awaitClear(sepStopwatchRef.get());
    // Return a weak reference to the parallel ClassLoader. This is the reference that should
    // eventually become clear if there are no other references to the ClassLoader.

    WeakReference<MyInt> signal = new WeakReference<>(canonical);
    canonical = null; // Hint to the JIT that canonical is unreachable

    GcFinalization.awaitClear(signal);
    assertThat(pool.intern(not)).isSameInstanceAs(not);
  }

  private static final class MyInt {
    private final int i;

    MyInt(int i) {
      this.i = i;
    }

    @Override

    WeakReference<MyInt> signal = new WeakReference<>(canonical);
    canonical = null; // Hint to the JIT that canonical is unreachable

    GcFinalization.awaitClear(signal);
    assertThat(pool.intern(not)).isSameInstanceAs(not);
  }

  private static final class MyInt {
    private final int i;

    MyInt(int i) {
      this.i = i;
    }

    @Override

          @Override
          public Object computeNext() {
            return new Object();
          }
        };
    WeakReference<Object> ref = doNextAndGetWeakReference(itr);
    GcFinalization.awaitClear(ref);
  }

  @GwtIncompatible // weak references
  private WeakReference<Object> doNextAndGetWeakReference(Iterator<Object> itr) {
    return new WeakReference<>(itr.next());
  }

          @Override
          public Object computeNext() {
            return new Object();
          }
        };
    WeakReference<Object> ref = doNextAndGetWeakReference(itr);
    GcFinalization.awaitClear(ref);
  }

  @GwtIncompatible // weak references
  private WeakReference<Object> doNextAndGetWeakReference(Iterator<Object> itr) {
    return new WeakReference<>(itr.next());
  }

          @Override
          public Object computeNext() {
            return new Object();
          }
        };
    WeakReference<Object> ref = doNextAndGetWeakReference(itr);
    GcFinalization.awaitClear(ref);
  }

  @GwtIncompatible // weak references
  private WeakReference<Object> doNextAndGetWeakReference(Iterator<Object> itr) {
    return new WeakReference<>(itr.next());
  }

          @Override
          public Object computeNext() {
            return new Object();
          }
        };
    WeakReference<Object> ref = doNextAndGetWeakReference(itr);
    GcFinalization.awaitClear(ref);
  }

  @GwtIncompatible // weak references
  private WeakReference<Object> doNextAndGetWeakReference(Iterator<Object> itr) {
    return new WeakReference<>(itr.next());
  }

  public void testGetIfPresent_doesNotPreventClassUnloading() throws Exception {
    WeakReference<?> shadowLoaderReference = doTestClassUnloading();
    GcFinalization.awaitClear(shadowLoaderReference);
  }

  // Create a second ClassLoader and use it to get a second version of the TestEnum class.
  // Run Enums.getIfPresent on that other TestEnum and then return a WeakReference containing the

  public void testGetIfPresent_doesNotPreventClassUnloading() throws Exception {
    WeakReference<?> shadowLoaderReference = doTestClassUnloading();
    GcFinalization.awaitClear(shadowLoaderReference);
  }

  // Create a second ClassLoader and use it to get a second version of the TestEnum class.
  // Run Enums.getIfPresent on that other TestEnum and then return a WeakReference containing the

   */
  private WeakReference<ReferenceQueue<Object>> queueReference;

  @Test
  public void testThatFinalizerStops() {
    weaklyReferenceQueue();
    GcFinalization.awaitClear(queueReference);
  }

  /** If we don't keep a strong reference to the reference object, it won't be enqueued. */
  @Nullable FinalizableWeakReference<Object> reference;