* };
 * x = null;  // Hint to the JIT that x is stack-unreachable
 * GcFinalization.await(latch);
 * }</pre>
 *
 * <p>Here's an example that uses a user-defined finalization predicate:
 *
 * <pre>{@code
 * final WeakHashMap<Object, Object> map = new WeakHashMap<>();
 * map.put(new Object(), Boolean.TRUE);
 * GcFinalization.awaitDone(new FinalizationPredicate() {
 *   public boolean isDone() {

 * };
 * x = null;  // Hint to the JIT that x is stack-unreachable
 * GcFinalization.await(latch);
 * }</pre>
 *
 * <p>Here's an example that uses a user-defined finalization predicate:
 *
 * <pre>{@code
 * final WeakHashMap<Object, Object> map = new WeakHashMap<>();
 * map.put(new Object(), Boolean.TRUE);
 * GcFinalization.awaitDone(new FinalizationPredicate() {
 *   public boolean isDone() {

    k1 *= C2;
    return k1;
  }

  private static int mixH1(int h1, int k1) {
    h1 ^= k1;
    h1 = Integer.rotateLeft(h1, 13);
    h1 = h1 * 5 + 0xe6546b64;
    return h1;
  }

  // Finalization mix - force all bits of a hash block to avalanche
  private static HashCode fmix(int h1, int length) {
    h1 ^= length;
    h1 ^= h1 >>> 16;
    h1 *= 0x85ebca6b;
    h1 ^= h1 >>> 13;
    h1 *= 0xc2b2ae35;

a <code>SetFinalizer</code> function that adds a finalizer to be called when
a particular object is no longer reachable by the program.
A call to <code>SetFinalizer(x, f)</code> is synchronized before the finalization call <code>f(x)</code>.
</p>

<h3 id="more">Additional Mechanisms</h3>

<p>
The <code>sync</code> package provides additional synchronization abstractions,

import static com.google.common.base.StandardSystemProperty.PATH_SEPARATOR;
import static java.util.concurrent.TimeUnit.SECONDS;

import com.google.common.collect.ImmutableList;
import com.google.common.testing.GcFinalization;
import java.io.Closeable;
import java.io.File;
import java.lang.ref.WeakReference;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.net.MalformedURLException;
import java.net.URL;

import static com.google.common.util.concurrent.FuturesGetCheckedInputs.UNCHECKED_EXCEPTION;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.testing.GcFinalization;
import com.google.common.util.concurrent.FuturesGetCheckedInputs.ExceptionWithBadConstructor;
import com.google.common.util.concurrent.FuturesGetCheckedInputs.ExceptionWithGoodAndBadConstructor;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Function;
import com.google.common.testing.GcFinalization;
import com.google.common.testing.TestLogHandler;
import com.google.j2objc.annotations.J2ObjCIncompatible;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.List;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Function;
import com.google.common.testing.GcFinalization;
import com.google.common.testing.TestLogHandler;
import com.google.j2objc.annotations.J2ObjCIncompatible;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.List;