* can be used with collections that may contain null. This collection is a collection of
           * non-null Entry objects (Entry objects that might contain null values but are not
           * themselves null), so we can treat it as a plain `Object[]`.
           */
          @SuppressWarnings("nullness")
          Object[] result = standardToArray();

          return null;
        }
      };

  // Escapes everything except [a-zA-Z0-9]
  private static final UnicodeEscaper SIMPLE_ESCAPER =
      new UnicodeEscaper() {
        @Override
        protected char @Nullable [] escape(int cp) {
          return ('a' <= cp && cp <= 'z') || ('A' <= cp && cp <= 'Z') || ('0' <= cp && cp <= '9')
              ? null

    }

    /**
     * @return Required active profile identifiers, never {@code null}.
     */
    public Set<String> getRequiredActiveProfileIds() {
        return getProfileIds(pa -> !pa.optional && pa.active);
    }

    /**
     * @return Optional active profile identifiers, never {@code null}.
     */
    public Set<String> getOptionalActiveProfileIds() {

     * Retrieve an <code>InetAddress</code>. If the address is not
     * an IP address and cannot be resolved <code>null</code> will
     * be returned.
     */
    public static InetAddress getInetAddress ( Properties props, String key, InetAddress def ) {
        String addr = props.getProperty(key);
        if ( addr != null ) {
            try {
                def = InetAddress.getByName(addr);
            }

    Cell[] as;
    long b, v;
    int[] hc;
    Cell a;
    int n;
    if ((as = cells) != null || !casBase(b = base, b + x)) {
      boolean uncontended = true;
      if ((hc = threadHashCode.get()) == null
          || as == null
          || (n = as.length) < 1
          || (a = as[(n - 1) & hc[0]]) == null
          || !(uncontended = a.cas(v = a.value, v + x))) retryUpdate(x, hc, uncontended);
    }
  }

    } 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

   * {@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")
      }

      assertThrows(NullPointerException.class, () -> entry.setValue(null));
      expectUnchanged();
    }
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testSetValueNullSupported() {
    for (Entry<K, V> entry : getMap().entrySet()) {
      if (entry.getKey().equals(k0())) {
        entry.setValue(null);
      }
    }
    expectReplacement(entry(k0(), (V) null));

  }

  public void testToOptionalSingleton() {
    assertThat(Stream.of(1).collect(toOptional())).hasValue(1);
  }

  public void testToOptionalNull() {
    Stream<@Nullable Object> stream = Stream.of((Object) null);
    assertThrows(NullPointerException.class, () -> stream.collect(toOptional()));
  }

  public void testToOptionalMultiple() {
    IllegalArgumentException expected =