return ImmutableMap.builder()
            .putAll(Lists.transform(keys, k -> Maps.immutableEntry(k, "dummy value")))
            .buildOrThrow();
      }
    },
    FORCE_JDK {
      @Override
      public Map<Object, Object> create(List<?> keys) {
        ImmutableMap.Builder<Object, Object> builder = ImmutableMap.builder();
        for (Object k : keys) {

 * strategies.
 *
 * <ul>
 *   <li>SafeAtomicHelper: uses Atomic FieldsUpdaters to implement synchronization
 *   <li>SynchronizedHelper: uses {@code synchronized} blocks for synchronization
 * </ul>
 *
 * To force selection of our fallback strategies we load {@link AggregateFutureState} (and all of
 * {@code com.google.common.util.concurrent}) in degenerate class loaders which make certain

  public void testAddAllAtIndex_nullSupported() {
    List<E> containsNull = singletonList(null);
    assertTrue("addAll(n, containsNull) should return true", getList().addAll(0, containsNull));
    /*
     * We need (E) to force interpretation of null as the single element of a
     * varargs array, not the array itself
     */
    expectAdded(0, (E) null);
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)

  public void testAddAll_nullSupported() {
    List<E> containsNull = singletonList(null);
    assertTrue("addAll(containsNull) should return true", collection.addAll(containsNull));
    /*
     * We need (E) to force interpretation of null as the single element of a
     * varargs array, not the array itself
     */
    expectAdded((E) null);
  }

  @CollectionFeature.Require(value = SUPPORTS_ADD, absent = ALLOWS_NULL_VALUES)

 * variety of sequences of the {@link Iterator#next}, {@link Iterator#hasNext} and {@link
 * Iterator#remove} operations. This utility takes the brute-force approach of trying <i>all</i>
 * possible sequences of these operations, up to a given number of steps. So, if the caller
 * specifies to use <i>n</i> steps, a total of <i>3^n</i> tests are actually performed.
 *

 * variety of sequences of the {@link Iterator#next}, {@link Iterator#hasNext} and {@link
 * Iterator#remove} operations. This utility takes the brute-force approach of trying <i>all</i>
 * possible sequences of these operations, up to a given number of steps. So, if the caller
 * specifies to use <i>n</i> steps, a total of <i>3^n</i> tests are actually performed.
 *

   * objects come from factory methods that are themselves {@code @Nullable}. In reality neither the
   * array nor its contents can be null, but it is not useful to force the use of {@code
   * requireNonNull} or the like just to assert that.
   *
   * <p>{@code EqualsTester} will always check that every object it is given returns false from

    BUILDER_PUT_ALL_ENTRIES {
      @Override
      public ImmutableBiMap<Object, Object> create(List<Entry<?, ?>> entries) {
        return ImmutableBiMap.builder().putAll(entries).buildOrThrow();
      }
    },
    FORCE_JDK {
      @Override
      public ImmutableBiMap<Object, Object> create(List<Entry<?, ?>> entries) {
        return ImmutableBiMap.builder().putAll(entries).buildJdkBacked();
      }
    };

  private static final ImmutableSet<Long> TEST_LONGS;

  private static int force32(int value) {
    // GWT doesn't consistently overflow values to make them 32-bit, so we need to force it.
    return value & 0xffffffff;
  }

  static {
    ImmutableSet.Builder<Integer> testIntsBuilder = ImmutableSet.builder();
    ImmutableSet.Builder<Long> testLongsBuilder = ImmutableSet.builder();

    public DecoupledClassLoader(URL[] urls) {
      super(urls);
    }

    @Override
    protected synchronized Class<?> loadClass(String name, boolean resolve)
        throws ClassNotFoundException {
      // Force Finalizer to load from this class loader, not its parent.
      if (name.equals(Finalizer.class.getName())) {
        Class<?> clazz = findClass(name);
        if (resolve) {
          resolveClass(clazz);
        }