protected static String formatFeatureSet(Set<? extends Feature<?>> features) {
    List<String> temp = new ArrayList<>();
    for (Feature<?> feature : features) {
      Object featureAsObject = feature; // to work around bogus JDK warning
      if (featureAsObject instanceof Enum) {
        Enum<?> f = (Enum<?>) featureAsObject;
        temp.add(f.getDeclaringClass().getSimpleName() + "." + feature);
      } else {

 * the rest not null -- and the test fails if no expected exception is thrown. {@code
 * NullPointerTester} uses best effort to pick non-null default values for many common JDK and Guava
 * types, and also for interfaces and public classes that have public parameter-less constructors.
 * When the non-null default value for a particular parameter type cannot be provided by {@code

        for (Annotation a : classOrMethod.getDeclaredAnnotations()) {
          /*
           * We avoid reflecting on NullMarked because its @Target(..., MODULE) causes problems
           * under JDK 8.
           */
          if (!(a instanceof NullMarked)
              && a.annotationType().isAnnotationPresent(TesterAnnotation.class)) {
            annotations.add(a);
          }
        }

  private static final byte[] ARRAY234 = {(byte) 2, (byte) 3, (byte) 4};

  private static final byte[] VALUES = {Byte.MIN_VALUE, -1, 0, 1, Byte.MAX_VALUE};

  // We need to test that our method behaves like the JDK method.
  @SuppressWarnings("InlineMeInliner")
  public void testHashCode() {
    for (byte value : VALUES) {
      assertThat(Bytes.hashCode(value)).isEqualTo(Byte.hashCode(value));
    }
  }

        Long.MIN_VALUE,
        Long.MAX_VALUE
      };

  private static final double[] VALUES = Doubles.concat(NUMBERS, new double[] {NaN});

  // We need to test that our method behaves like the JDK method.
  @SuppressWarnings("InlineMeInliner")
  public void testHashCode() {
    for (double value : VALUES) {
      assertThat(Doubles.hashCode(value)).isEqualTo(Double.hashCode(value));
    }
  }

  // We need to test that our method behaves like the JDK method.
  @SuppressWarnings("InlineMeInliner")
  public void testHashCode() {
    for (long value : VALUES) {
      assertWithMessage("hashCode for %s", value)
          .that(Longs.hashCode(value))
          .isEqualTo(Long.hashCode(value));
    }
  }

  // We need to test that our method behaves like the JDK method.
  @SuppressWarnings("InlineMeInliner")

  private static final short GREATEST = Short.MAX_VALUE;

  private static final short[] VALUES = {LEAST, (short) -1, (short) 0, (short) 1, GREATEST};

  // We need to test that our method behaves like the JDK method.
  @SuppressWarnings("InlineMeInliner")
  public void testHashCode() {
    for (short value : VALUES) {
      assertThat(Shorts.hashCode(value)).isEqualTo(Short.hashCode(value));
    }
  }

  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testDifferentComparator_serialization() {
    // don't use Collections.reverseOrder(); it didn't reserialize to the same instance in JDK5
    Comparator<Comparable<?>> comparator = Ordering.natural().reverse();
    SortedSet<String> set =
        new ImmutableSortedSet.Builder<String>(comparator).add("a", "b", "c").build();

   * typically by writing {@code (Function<Object, String> & Serializable) Object::toString}.
   *
   * <p>For more important information about the transition from Guava's {@link Function} class to
   * the JDK {@link java.util.function.Function} class, see {@link Function}.
   */
  public static Function<Object, String> toStringFunction() {
    return ToStringFunction.INSTANCE;
  }

  // enum singleton pattern

   * typically by writing {@code (Function<Object, String> & Serializable) Object::toString}.
   *
   * <p>For more important information about the transition from Guava's {@link Function} class to
   * the JDK {@link java.util.function.Function} class, see {@link Function}.
   */
  public static Function<Object, String> toStringFunction() {
    return ToStringFunction.INSTANCE;
  }

  // enum singleton pattern