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

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

import static java.util.concurrent.TimeUnit.SECONDS;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
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;