* Ein spezieller Fall ist `204`, „No Content“ („Kein Inhalt“). Diese Response wird verwendet, wenn es keinen Inhalt gibt, der zum Client zurückgeschickt wird, diese Response hat also keinen Body.
* **`300`** und darüber steht für „Redirection“ („Umleitung“).  Responses mit diesen Statuscodes können einen oder keinen Body haben, mit Ausnahme von `304`, „Not Modified“ („Nicht verändert“), welche keinen haben darf.

import java.util.Collections;
import java.util.Iterator;
import java.util.NoSuchElementException;
import junit.framework.TestCase;

/**
 * Unit test for {@link MinimalIterable}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
public class MinimalIterableTest extends TestCase {

  public void testOf_empty() {
    Iterable<String> iterable = MinimalIterable.<String>of();

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Implementation of {@link ImmutableSet} with exactly one element.
 *
 * @author Kevin Bourrillion
 * @author Nick Kralevich
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
@ElementTypesAreNonnullByDefault

import com.google.common.collect.testing.SampleElements.Enums;
import java.util.List;
import java.util.Set;

/**
 * An abstract TestSetGenerator for generating sets containing enum values.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestEnumSetGenerator implements TestSetGenerator<AnEnum> {
  @Override
  public SampleElements<AnEnum> samples() {

import com.google.common.collect.testing.SampleElements.Enums;
import java.util.List;
import java.util.Set;

/**
 * An abstract TestSetGenerator for generating sets containing enum values.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestEnumSetGenerator implements TestSetGenerator<AnEnum> {
  @Override
  public SampleElements<AnEnum> samples() {

/**
 * A generic JUnit test which tests {@code listIterator} operations on a list. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.ListTestSuiteBuilder}.
 *
 * @author Chris Povirk
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@ElementTypesAreNonnullByDefault

import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

/**
 * Implementation helper for {@link TestMapGenerator} for use with enum maps.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestEnumMapGenerator implements TestMapGenerator<AnEnum, String> {

  @Override

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Implementation of {@link ImmutableSet} with exactly one element.
 *
 * @author Kevin Bourrillion
 * @author Nick Kralevich
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
@ElementTypesAreNonnullByDefault

/**
 * A generic JUnit test which tests {@code toString()} operations on a collection. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")

import com.google.common.annotations.VisibleForTesting;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Implementation of {@link ImmutableList} backed by a simple array.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
@ElementTypesAreNonnullByDefault