.addEqualityGroup(isNull)
        .addEqualityGroup(Equivalence.identity().equivalentTo("1"))
        .testEquals();
  }

  /*
   * We use large numbers to avoid the integer cache. Normally, we'd accomplish that merely by using
   * `new Integer` (as we do) instead of `Integer.valueOf`. However, under J2KT, `new Integer`
   * gets translated back to `Integer.valueOf` because that is the only thing J2KT can support. And

  public static <T extends @Nullable Object> Collector<T, ?, T> onlyElement() {
    return (Collector) ONLY_ELEMENT;
  }

  /**
   * This atrocity is here to let us report several of the elements in the stream if there were more
   * than one, not just two.
   */
  @SuppressWarnings("EmptyList") // ImmutableList doesn't support nullable element types
  private static final class ToOptionalState {
    static final int MAX_EXTRAS = 4;

   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.
   * (And even if annotations on local variables were permitted as an optional hint, no annotation
   * would be the right tool for the job here: {@code @Nullable} is the annotation that we're trying

    /**
     * {@return the dependency scope for the given identifier, or {@code null} if none}.
     * The identifiers are usually in lower cases with {@code '-'} instead of {@code '_'}
     * as word separator.
     *
     * @param id the identifier of the scope (case-sensitive)
     */
    public static DependencyScope forId(String id) {
        return IDS.get(id);
    }

    private final String id;

    expectUnchanged();
    assertTrue(collection.contains(e0()));
  }

  /*
   * AbstractCollection fails the removeAll(null) test when the subject
   * collection is empty, but we'd still like to test removeAll(null) when we
   * can. We split the test into empty and non-empty cases. This allows us to
   * suppress only the former.
   */

  @CollectionFeature.Require(SUPPORTS_REMOVE)

    latch.countDown();

    exec.shutdown();
    exec.awaitTermination(100, MILLISECONDS);
  }

  /**
   * Tests that all listeners complete, even if they were added before or after the future was
   * finishing. Also acts as a concurrency test to make sure the locking is done correctly when a
   * future is finishing so that no listeners can be lost.
   */

    }
    return standardAddAll(collection);
  }

  @Override
  @J2ktIncompatible // Incompatible return type change. Use inherited implementation
  public Object[] toArray() {
    /*
     * If we could, we'd declare the no-arg `Collection.toArray()` to return "Object[] but elements
     * have the same nullness as E." Since we can't, we declare it to return nullable elements, and

  public static <T extends @Nullable Object> Collector<T, ?, T> onlyElement() {
    return (Collector) ONLY_ELEMENT;
  }

  /**
   * This atrocity is here to let us report several of the elements in the stream if there were more
   * than one, not just two.
   */
  @SuppressWarnings("EmptyList") // ImmutableList doesn't support nullable element types
  private static final class ToOptionalState {
    static final int MAX_EXTRAS = 4;

  static final ImmutableMap<String, String> TEST_STRINGS =
      ImmutableMap.<String, String>builder()
          .put("empty", "")
          .put("1 char", "0")
          .put("1 word", "hello")
          .put("2 words", "hello world")
          .put("\\n line break", "hello\nworld")
          .put("\\r line break", "hello\rworld")
          .put("\\r\\n line break", "hello\r\nworld")

    long signifRounded = increment ? signifFloor + 1 : signifFloor;
    long bits = (long) (exponent + EXPONENT_BIAS) << SIGNIFICAND_BITS;
    bits += signifRounded;
    /*
     * If signifRounded == 2^53, we'd need to set all of the significand bits to zero and add 1 to
     * the exponent. This is exactly the behavior we get from just adding signifRounded to bits