* the garbage collector reclaims the referent. This is a simpler alternative to using a {@link
 * ReferenceQueue}.
 *
 * @author Bob Lee
 * @since 2.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public abstract class FinalizableWeakReference<T> extends WeakReference<T>
    implements FinalizableReference {
  /**

import com.google.errorprone.annotations.DoNotMock;

/**
 * Implemented by references that have code to run after garbage collection of their referents.
 *
 * @see FinalizableReferenceQueue
 * @author Bob Lee
 * @since 2.0
 */
@DoNotMock("Use an instance of one of the Finalizable*Reference classes")
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public interface FinalizableReference {
  /**

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import javax.annotation.CheckForNull;

/**
 * Wraps an exception that occurred during a computation.
 *
 * @author Bob Lee
 * @since 2.0
 * @deprecated This exception is no longer thrown by {@code com.google.common}. Previously, it was
 *     thrown by {@link MapMaker} computing maps. When support for computing maps was removed from

 * {@link ReferenceQueue}.
 *
 * <p>Unlike a normal phantom reference, this reference will be cleared automatically.
 *
 * @author Bob Lee
 * @since 2.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public abstract class FinalizablePhantomReference<T> extends PhantomReference<T>
    implements FinalizableReference {
  /**

import java.io.Serializable;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Equivalence applied on functional result.
 *
 * @author Bob Lee
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class FunctionalEquivalence<F, T> extends Equivalence<F> implements Serializable {

  private static final long serialVersionUID = 0;

import com.google.errorprone.annotations.DoNotMock;

/**
 * Implemented by references that have code to run after garbage collection of their referents.
 *
 * @see FinalizableReferenceQueue
 * @author Bob Lee
 * @since 2.0
 */
@DoNotMock("Use an instance of one of the Finalizable*Reference classes")
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public interface FinalizableReference {
  /**

 * the garbage collector reclaims the referent. This is a simpler alternative to using a {@link
 * ReferenceQueue}.
 *
 * @author Bob Lee
 * @since 2.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public abstract class FinalizableSoftReference<T> extends SoftReference<T>
    implements FinalizableReference {
  /**

 * {@link ReferenceQueue}.
 *
 * <p>Unlike a normal phantom reference, this reference will be cleared automatically.
 *
 * @author Bob Lee
 * @since 2.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public abstract class FinalizablePhantomReference<T> extends PhantomReference<T>
    implements FinalizableReference {
  /**

import java.io.Serializable;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Equivalence applied on functional result.
 *
 * @author Bob Lee
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class FunctionalEquivalence<F, T> extends Equivalence<F> implements Serializable {

  private static final long serialVersionUID = 0;

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

/**
 * 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