import com.google.common.annotations.J2ktIncompatible;
import java.lang.ref.PhantomReference;
import java.lang.ref.ReferenceQueue;
import org.jspecify.annotations.Nullable;

/**
 * Phantom reference with a {@code finalizeReferent()} method which a background thread invokes
 * after the garbage collector reclaims the referent. This is a simpler alternative to using a
 * {@link ReferenceQueue}.
 *

      ReferenceQueue<Object> queue,
      PhantomReference<Object> frqReference) {
    /*
     * We use finalizableReferenceClass for two things:
     *
     * 1) To invoke FinalizableReference.finalizeReferent()
     *
     * 2) To detect when FinalizableReference's class loader has to be garbage collected, at which
     * point, Finalizer can stop running
     */

      ReferenceQueue<Object> queue,
      PhantomReference<Object> frqReference) {
    /*
     * We use finalizableReferenceClass for two things:
     *
     * 1) To invoke FinalizableReference.finalizeReferent()
     *
     * 2) To detect when FinalizableReference's class loader has to be garbage collected, at which
     * point, Finalizer can stop running
     */

    public MyFinalizableWeakReference(Object x, FinalizableReferenceQueue queue) {
      super(x, queue);
    }

    @Override
    public void finalizeReferent() {}
  }

  private WeakReference<ClassLoader> useFrqInSeparateLoader() throws Exception {
    ClassLoader myLoader = getClass().getClassLoader();

    public MyFinalizableWeakReference(Object x, FinalizableReferenceQueue queue) {
      super(x, queue);
    }

    @Override
    public void finalizeReferent() {}
  }

  private WeakReference<ClassLoader> useFrqInSeparateLoader() throws Exception {
    ClassLoader myLoader = getClass().getClassLoader();

    final CountDownLatch latch;

    FinalizableReference(Object referent, CountDownLatch latch) {
      super(referent, referenceQueue);
      this.latch = latch;
    }

    @Override
    public void finalizeReferent() {
      references.remove(this);
      latch.countDown();
    }
  }

  @FormatMethod
  private static RuntimeException formatRuntimeException(String format, Object... args) {

    final State state;

    FinalizableReference(FbosByteSource referent) {
      super(referent, referenceQueue);
      this.state = referent.state;
    }

    @Override
    public void finalizeReferent() {
      references.remove(this);
      try {
        state.reset();
      } catch (Throwable t) {
        t.printStackTrace(System.err);
      }
    }
  }

    final CountDownLatch latch;

    FinalizableReference(Object referent, CountDownLatch latch) {
      super(referent, referenceQueue);
      this.latch = latch;
    }

    @Override
    public void finalizeReferent() {
      references.remove(this);
      latch.countDown();
    }
  }

  @FormatMethod
  private static RuntimeException formatRuntimeException(String format, Object... args) {

    final State<?> state;

    FinalizableReference(ClosingFuture<?> referent) {
      super(referent, referenceQueue);
      this.state = referent.state;
    }

    @Override
    public void finalizeReferent() {
      references.remove(this);
      state.closeIfLeaked();
    }
  }

  /** Ensures that {@code o} is not garbage collected until this point in the code. */
  @VisibleForTesting