private static final @Nullable Object jla = getJla();

  /**
   * The "getStackTraceElementMethod" method, only available on some JDKs so we use reflection to
   * find it when available. When this is null, use the slow way.
   */
  @J2ktIncompatible @GwtIncompatible // java.lang.reflect
  private static final @Nullable Method getStackTraceElementMethod =

import java.util.ListIterator;
import org.jspecify.annotations.Nullable;

/**
 * An iterator that transforms a backing list iterator; for internal use. This avoids the object
 * overhead of constructing a {@link Function} for internal methods.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class TransformedListIterator<F extends @Nullable Object, T extends @Nullable Object>

import java.util.ListIterator;
import org.jspecify.annotations.Nullable;

/**
 * An iterator that transforms a backing list iterator; for internal use. This avoids the object
 * overhead of constructing a {@link Function} for internal methods.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class TransformedListIterator<F extends @Nullable Object, T extends @Nullable Object>

 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingMultiset<E extends @Nullable Object> extends ForwardingCollection<E>
    implements Multiset<E> {

  /** Constructor for use by subclasses. */
  protected ForwardingMultiset() {}

  @Override
  protected abstract Multiset<E> delegate();

  @Override
  public int count(@Nullable Object element) {
    return delegate().count(element);
  }

import java.util.List;
import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A container class for the five sample elements we need for testing.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public class SampleElements<E extends @Nullable Object> implements Iterable<E> {
  // TODO: rename e3, e4 => missing1, missing2
  private final E e0;

    CountDownLatch isInterruptibleRegistered = new CountDownLatch(1);
    SlowChannel slowChannel = new SlowChannel();
    InterruptibleTask<@Nullable Void> task =
        new InterruptibleTask<@Nullable Void>() {
          @Override
          @Nullable Void runInterruptibly() throws Exception {
            slowChannel.doBegin();
            isInterruptibleRegistered.countDown();
            try {

    CountDownLatch isInterruptibleRegistered = new CountDownLatch(1);
    SlowChannel slowChannel = new SlowChannel();
    InterruptibleTask<@Nullable Void> task =
        new InterruptibleTask<@Nullable Void>() {
          @Override
          @Nullable Void runInterruptibly() throws Exception {
            slowChannel.doBegin();
            isInterruptibleRegistered.countDown();
            try {

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link GcFinalization}.
 *
 * @author Martin Buchholz
 * @author mike nonemacher
 */

@NullUnmarked
public class GcFinalizationTest extends TestCase {

import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.NoSuchElementException;
import org.jspecify.annotations.Nullable;

/**
 * This class provides a skeletal implementation of the {@code Iterator} interface, to make this
 * interface easier to implement for certain types of data sources.
 *

   * java.util.Objects#equals} instead.
   */
  @SuppressWarnings("InlineMeSuggester") // would introduce fully qualified references to Objects
  public static boolean equal(@Nullable Object a, @Nullable Object b) {
    return java.util.Objects.equals(a, b);
  }

  /**
   * Generates a hash code for multiple values. The hash code is generated by calling {@link