*
       * Android API level 26 and JVM8 both let our Error propagate directly the first time and
       * throw NoClassDefFoundError thereafter. This is the proper behavior according to the spec.
       * See https://docs.oracle.com/javase/specs/jls/se8/html/jls-12.html#jls-12.4.2 (steps #11 and
       * #5).
       *
       * Note that that "first time" might happen in a test other than
       * testLexicographicalComparatorChoice!

   * mod(-7, 4) == 1
   * mod(-1, 4) == 3
   * mod(-8, 4) == 0
   * mod(8, 4) == 0
   * }</pre>
   *
   * @throws ArithmeticException if {@code m <= 0}
   * @see <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.17.3">
   *     Remainder Operator</a>
   */
  @GwtIncompatible // TODO
  public static int mod(long x, int m) {
    // Cast is safe because the result is guaranteed in the range [0, m)

       *
       * Android API level 26 and JVM8 both let our Error propagate directly the first time and
       * throw NoClassDefFoundError thereafter. This is the proper behavior according to the spec.
       * See https://docs.oracle.com/javase/specs/jls/se8/html/jls-12.html#jls-12.4.2 (steps #11 and
       * #5).
       *
       * Note that that "first time" might happen in a test other than
       * testLexicographicalComparatorChoice!

  // but essentially each line will be a call to a Preconditions method that, but for a documented
  // change would be a compiler error.
  // See http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.12.2 for the spec on
  // how javac selects overloads
  @SuppressWarnings("null")
  public void overloadSelection() {
    Boolean boxedBoolean = null;
    boolean aBoolean = true;
    Long boxedLong = null;

  // but essentially each line will be a call to a Preconditions method that, but for a documented
  // change would be a compiler error.
  // See http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.12.2 for the spec on
  // how javac selects overloads
  @SuppressWarnings("null")
  public void overloadSelection() {
    Boolean boxedBoolean = null;
    boolean aBoolean = true;
    Long boxedLong = null;

      // extensive testing
      try {
        return Double.parseDouble(string);
      } catch (NumberFormatException e) {
        // Double.parseDouble has changed specs several times, so fall through
        // gracefully
      }
    }
    return null;
  }

      // extensive testing
      try {
        return Float.parseFloat(string);
      } catch (NumberFormatException e) {
        // Float.parseFloat has changed specs several times, so fall through
        // gracefully
      }
    }
    return null;
  }

   * mod(-7, 4) == 1
   * mod(-1, 4) == 3
   * mod(-8, 4) == 0
   * mod(8, 4) == 0
   * }</pre>
   *
   * @throws ArithmeticException if {@code m <= 0}
   * @see <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.17.3">
   *     Remainder Operator</a>
   */
  public static int mod(int x, int m) {
    if (m <= 0) {
      throw new ArithmeticException("Modulus " + m + " must be > 0");
    }

    // Valid radix values are Character.MIN_RADIX to Character.MAX_RADIX,
    // inclusive.
    //
    // Note: According to the spec, a NumberFormatException is thrown for a number that is not
    // parseable, but the spec doesn't seem to say which exception is thrown for an invalid radix.
    // In contrast to the JVM, Kotlin native throws an Illegal argument exception in this case

  public void testFromNullable() {
    Optional<String> optionalName = Optional.fromNullable("bob");
    assertEquals("bob", optionalName.get());
  }

  public void testFromNullable_null() {
    // not promised by spec, but easier to test
    assertSame(Optional.absent(), Optional.fromNullable(null));
  }

  public void testIsPresent_no() {
    assertFalse(Optional.absent().isPresent());
  }