*/
  public void testAwaitFullGc() {
    CountDownLatch finalizerRan = new CountDownLatch(1);
    WeakReference<Object> ref = createWeakReferenceWithFinalizer(finalizerRan);

    // Don't copy this into your own test!
    // Use e.g. awaitClear or await(CountDownLatch) instead.
    GcFinalization.awaitFullGc();

    // Attempt to help with some flakiness that we've seen: b/387521512.
    GcFinalization.awaitFullGc();

     * fastest possible implementation, which delegates to the array overload of String.join.
     *
     * In theory, we can quickly determine the size of any Collection. However, thanks to
     * regrettable implementations like our own Sets.filter, Collection.size() is sometimes a
     * linear-time operation, and it can even have side effects. Thus, we limit the special case to

  If you do not, you risk allowing unauthorized users to access your apiserver.
  * You *MUST* set `--anonymous-auth=false` flag on your federation apiserver unless you are a developer testing this feature and understand it.
    If you do not, you risk allowing unauthorized users to access your federation apiserver.

   */
  public void testAwaitFullGc() {
    CountDownLatch finalizerRan = new CountDownLatch(1);
    WeakReference<Object> ref = createWeakReferenceWithFinalizer(finalizerRan);

    // Don't copy this into your own test!
    // Use e.g. awaitClear or await(CountDownLatch) instead.
    GcFinalization.awaitFullGc();

    // Attempt to help with some flakiness that we've seen: b/387521512.
    GcFinalization.awaitFullGc();

  /**
   * Implementations of {@link #computeNext} <b>must</b> invoke this method when there are no
   * elements left in the iteration.
   *
   * @return {@code null}; a convenience so your {@code computeNext} implementation can use the
   *     simple statement {@code return endOfData();}
   */
  @CanIgnoreReturnValue
  protected final @Nullable T endOfData() {
    state = State.DONE;
    return null;

// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class MapComputeIfAbsentTester<K, V> extends AbstractMapTester<K, V> {

  @MapFeature.Require(SUPPORTS_PUT)
  public void testComputeIfAbsent_supportedAbsent() {
    assertEquals(

// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class MapPutIfAbsentTester<K, V> extends AbstractMapTester<K, V> {

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutIfAbsent_supportedAbsent() {
    assertNull(

// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class MapReplaceEntryTester<K, V> extends AbstractMapTester<K, V> {

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testReplaceEntry_supportedPresent() {
    try {

  }

  /**
   * Returns the empty map. This map behaves and performs comparably to {@link
   * Collections#emptyMap}, and is preferable mainly for consistency and maintainability of your
   * code.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked")
  public static <K, V> ImmutableMap<K, V> of() {

   *     illustrated in the example above
   * @deprecated To preserve behavior, use {@code throw e} or {@code throw new RuntimeException(e)}
   *     directly, or use a combination of {@link #throwIfUnchecked} and {@code throw new
   *     RuntimeException(e)}. But consider whether users would be better off if your API threw a