public T or(Supplier<? extends T> supplier) {
    return checkNotNull(
        supplier.get(), "use Optional.orNull() instead of a Supplier that returns null");
  }

  @Override
  @CheckForNull
  public T orNull() {
    return null;
  }

  @Override
  public Set<T> asSet() {
    return Collections.emptySet();
  }

  @Override
  public <V> Optional<V> transform(Function<? super T, V> function) {

            return (Calendar) o;
        }
        final java.util.Date date = DateConversionUtil.toDate(o, pattern);
        if (date != null) {
            final Calendar cal = Calendar.getInstance();
            cal.setTime(date);
            return cal;
        }
        return null;
    }

    /**
     * ローカルの{@link TimeZone}と{@link Locale}をもつ{@link Calendar}に変換します。
     *
     * @param calendar

     *
     * @param version the version to test, must not be {@code null}
     * @return {@code true} if this range contains the specified version, {@code false} otherwise
     */
    boolean contains(@Nonnull Version version);

    /**
     * Returns the upper boundary of this range, or {@code null} if none.
     */
    @Nullable
    Boundary getUpperBoundary();

    /**

    }

    protected String getJdkVersion() {
        return JDK_VERSION;
    }

    protected boolean canDetectActivation(Profile profile) {
        return profile.getActivation() != null
                && profile.getActivation().getJdk() != null
                && !profile.getActivation().getJdk().isEmpty();
    }

     *            <code>null</code>.
     * @param request The model building request that holds further settings, must not be {@code null}.
     * @param problems The container used to collect problems that were encountered, must not be {@code null}.
     */
    void injectLifecycleBindings(Model model, ModelBuildingRequest request, ModelProblemCollector problems);

     *
     * @param problems The problems that cause this exception, must not be {@code null}.
     */
    public ToolchainsBuildingException(List<Problem> problems) {
        super(toMessage(problems));

        this.problems = new ArrayList<>();
        if (problems != null) {
            this.problems.addAll(problems);
        }
    }

    /**

    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().removeAll(null) doesn't throws NPE.
    }
  }

  @Override
  public void testEntrySetRetainAllNullFromEmpty() {
    try {
      super.testEntrySetRetainAllNullFromEmpty();
    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().retainAll(null) doesn't throws NPE.
    }
  }

  @Override

        int len = this.length;

        if ( this.next != null ) {
            int nextStart = dstIndex;
            dstIndex += this.next.encode(dst, dstIndex);
            int off = nextStart - start;
            SMBUtil.writeInt4(off, dst, start + 20);
            len += dstIndex - nextStart;
        }

        if ( this.digest != null ) {

   * {@link Equivalence#equivalent} returns {@code true} if both values are null, or if neither
   * value is null and {@link Object#equals} returns {@code true}. {@link Equivalence#hash} returns
   * {@code 0} if passed a null value.
   *
   * @since 13.0
   * @since 8.0 (in Equivalences with null-friendly behavior)
   * @since 4.0 (in Equivalences)
   */
  public static Equivalence<Object> equals() {

    val mainMethod =
      Class.forName(className)
        .methods.find { it.name == "main" }
    try {
      if (mainMethod != null) {
        if (mainMethod.parameters.isEmpty()) {
          mainMethod.invoke(null)
        } else {
          mainMethod.invoke(null, arrayOf<String>())
        }
      } else {
        System.err.println("No main for $className")
      }