* backing collection.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial")
@ElementTypesAreNonnullByDefault
abstract class ImmutableAsList<E> extends ImmutableList<E> {
  abstract ImmutableCollection<E> delegateCollection();

  @Override
  public boolean contains(@CheckForNull Object target) {

 * backing collection.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial")
@ElementTypesAreNonnullByDefault
abstract class ImmutableAsList<E> extends ImmutableList<E> {
  abstract ImmutableCollection<E> delegateCollection();

  @Override
  public boolean contains(@CheckForNull Object target) {

  private static Runnable runnableThrowing(final RuntimeException e) {
    return new Runnable() {
      @Override
      public void run() {
        throw e;
      }
    };
  }

  @SuppressWarnings("serial")
  private static class SampleCheckedException extends Exception {}

/**
 * Implementation of {@link ImmutableMap} backed by a non-empty {@link java.util.EnumMap}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // we're overriding default serialization
@ElementTypesAreNonnullByDefault
final class ImmutableEnumMap<K extends Enum<K>, V> extends IteratorBasedImmutableMap<K, V> {

/**
 * Implementation of {@link ImmutableSet} backed by a non-empty {@link java.util.EnumSet}.
 *
 * @author Jared Levy
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // we're overriding default serialization
@ElementTypesAreNonnullByDefault
final class ImmutableEnumSet<E extends Enum<E>> extends ImmutableSet<E> {
  static <E extends Enum<E>> ImmutableSet<E> asImmutable(EnumSet<E> set) {

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

/**
 * Unit test for {@link PeekingIterator}.
 *
 * @author Mick Killianey
 */
@SuppressWarnings("serial") // No serialization is used in this test
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class PeekingIteratorTest extends TestCase {

  /**

/**
 * GWT implementation of {@link ImmutableSet} that forwards to another {@code Set} implementation.
 *
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
@SuppressWarnings("serial") // Serialization only done in GWT.
public abstract class ForwardingImmutableSet<E> extends ImmutableSet<E> {
  private final transient Set<E> delegate;

  ForwardingImmutableSet(Set<E> delegate) {

import java.util.HashMap;

/**
 * GWT emulation of {@link RegularImmutableBiMap}.
 *
 * @author Jared Levy
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
@SuppressWarnings("serial")
class RegularImmutableBiMap<K, V> extends ImmutableBiMap<K, V> {
  static final RegularImmutableBiMap<Object, Object> EMPTY =
      new RegularImmutableBiMap<Object, Object>();

import com.google.common.annotations.J2ktIncompatible;
import javax.annotation.CheckForNull;

/**
 * A descending wrapper around an {@code ImmutableSortedMultiset}
 *
 * @author Louis Wasserman
 */
@SuppressWarnings("serial") // uses writeReplace, not default serialization
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class DescendingImmutableSortedMultiset<E> extends ImmutableSortedMultiset<E> {

import com.google.common.annotations.J2ktIncompatible;
import javax.annotation.CheckForNull;

/**
 * A descending wrapper around an {@code ImmutableSortedMultiset}
 *
 * @author Louis Wasserman
 */
@SuppressWarnings("serial") // uses writeReplace, not default serialization
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class DescendingImmutableSortedMultiset<E> extends ImmutableSortedMultiset<E> {