* number of well-known problems. Here is how you might use this class instead:
 *
 * <pre>{@code
 * public class MyServer implements Closeable {
 *   private static final FinalizableReferenceQueue frq = new FinalizableReferenceQueue();
 *   // You might also share this between several objects.
 *
 *   private static final Set<Reference<?>> references = Sets.newConcurrentHashSet();

/**
 * Unit test for {@link FinalizableReferenceQueue}.
 *
 * @author Bob Lee
 */
// - depends on details of GC and classloading
// - .class files aren't available
// - possibly no real concept of separate ClassLoaders?
@AndroidIncompatible
@GwtIncompatible
public class FinalizableReferenceQueueTest extends TestCase {

  private @Nullable FinalizableReferenceQueue frq;

  @Override

  /*
   * The following tests check that the use of FinalizableReferenceQueue does not prevent the
   * ClassLoader that loaded that class from later being garbage-collected. If anything continues
   * to reference the FinalizableReferenceQueue class then its ClassLoader cannot be
   * garbage-collected, even if there are no more instances of FinalizableReferenceQueue itself.
   * The code in FinalizableReferenceQueue goes to considerable trouble to ensure that there are