* java.util.function.Function}, making conversion code necessary only in one direction. At that
 * time, this interface will be officially discouraged.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface Function<F extends @Nullable Object, T extends @Nullable Object>
{
  /**

 * necessary.
 *
 * <p>See the Guava User Guide section on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#iterables">{@code
 * Iterators}</a>.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Iterators {
  private Iterators() {}

  /**

 * {@link Lists}, {@link Maps} and {@link Queues}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#sets">{@code Sets}</a>.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @author Chris Povirk
 * @since 2.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Sets {
  private Sets() {}

  /**

 * utilities.
 *
 * <p>A comparison of the various hash functions can be found <a
 * href="http://goo.gl/jS7HH">here</a>.
 *
 * @author Kevin Bourrillion
 * @author Dimitris Andreou
 * @author Kurt Alfred Kluever
 * @since 11.0
 */
@ElementTypesAreNonnullByDefault
public final class Hashing {
  /**

 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#multisets">{@code
 * Multisets}</a>.
 *
 * @author Kevin Bourrillion
 * @author Mike Bostock
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Multisets {
  private Multisets() {}

  /**

 * absolutely necessary.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#iterables">{@code
 * Iterables}</a>.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Iterables {
  private Iterables() {}

 *
 * <h3>More information</h3>
 *
 * <p>See the Guava User Guide on <a
 * href="https://github.com/google/guava/wiki/PreconditionsExplained">using {@code
 * Preconditions}</a>.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Preconditions {
  private Preconditions() {}

  private interface Impossible {}

  /**

import java.util.concurrent.CopyOnWriteArrayList;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

/**
 * Unit test for {@code Lists}.
 *
 * @author Kevin Bourrillion
 * @author Mike Bostock
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class ListsTest extends TestCase {

 * {@link ImmutableCollection}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 * @since 2.0
 */
@DoNotMock("Use ImmutableMap.of or another implementation")
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // we're overriding default serialization

import java.util.concurrent.CopyOnWriteArrayList;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

/**
 * Unit test for {@code Lists}.
 *
 * @author Kevin Bourrillion
 * @author Mike Bostock
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class ListsTest extends TestCase {