Optional<Number> first = (Optional<Number>) numbers.first();
    Number value = first.or(0.5); // fine
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    NullPointerTester npTester = new NullPointerTester();
    npTester.testAllPublicConstructors(Optional.class);
    npTester.testAllPublicStaticMethods(Optional.class);

    Type elementType = List.class.getTypeParameters()[0];
    assertEquals(elementType.toString(), Types.toString(elementType));
  }

  public void testNullPointers() {
    new NullPointerTester().testStaticMethods(Types.class, Visibility.PACKAGE);
  }

    assertThrows(UnsupportedOperationException.class, () -> j.withKeyValueSeparator("/"));
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicStaticMethods(Joiner.class);
    tester.testInstanceMethods(Joiner.on(","), NullPointerTester.Visibility.PACKAGE);

    assertThrows(IllegalArgumentException.class, () -> builder.setCount("a", -2));
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicStaticMethods(ImmutableMultiset.class);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester

    assertThrows(UnsupportedOperationException.class, () -> j.withKeyValueSeparator("/"));
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicStaticMethods(Joiner.class);
    tester.testInstanceMethods(Joiner.on(","), NullPointerTester.Visibility.PACKAGE);

    ImmutableSortedMultiset.Builder<String> builder = ImmutableSortedMultiset.naturalOrder();
    assertThrows(IllegalArgumentException.class, () -> builder.setCount("a", -2));
  }

  public void testNullPointers() {
    new NullPointerTester().testAllPublicStaticMethods(ImmutableSortedMultiset.class);
  }

  public void testSerialization_empty() {
    Collection<String> c = ImmutableSortedMultiset.of();

    assertEquals(asList("a", "b", "c", "d"), list);
  }

  // Basic tests

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicStaticMethods(ImmutableList.class);
    tester.testAllPublicInstanceMethods(ImmutableList.of(1, 2, 3));
  }

  /* The names of the expected method that tests null checks. */
  private static final ImmutableList<String> NULL_TEST_METHOD_NAMES =
      ImmutableList.of(
          "testNulls", "testNull",
          "testNullPointers", "testNullPointer",
          "testNullPointerExceptions", "testNullPointerException");

  /* The names of the expected method that tests serializable. */

    short s = 2;
    checkState(boxedBoolean.booleanValue(), "", s);
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    /*
     * Don't bother testing: Preconditions defines a bunch of methods that accept a template (or
     * even entire message) that simultaneously:
     *

        .setExpectation(Double.NEGATIVE_INFINITY, UP, FLOOR)
        .roundUnnecessaryShouldThrow()
        .test();
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    NullPointerTester tester = new NullPointerTester();
    tester.setDefault(BigInteger.class, ONE);
    tester.setDefault(int.class, 1);
    tester.setDefault(long.class, 1L);