*
   * @throws IllegalArgumentException if the stream consists of two or more elements.
   * @throws NullPointerException if any element in the stream is {@code null}.
   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be
   *     {@code null}) and returns {@code Optional.empty()} if it has none.
   */
  @SuppressWarnings("unchecked")
  public static <T> Collector<T, ?, Optional<T>> toOptional() {

                }));
    expectReplacement(entry(getKeyForNullValue(), v3()));
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
  public void testMergeAbsentNullKey() {
    assertEquals(
        "Map.merge(null, value, function) should return value",
        v3(),
        getMap()
            .merge(
                null,
                v3(),

    private var bodyVar: MockResponseBody? = null
    private var socketHandlerVar: SocketHandler? = null
    private var webSocketListenerVar: WebSocketListener? = null

    public var body: MockResponseBody?
      get() = bodyVar
      private set(value) {
        bodyVar = value
        socketHandlerVar = null
        webSocketListenerVar = null
      }

    if (inflater.bytesRead < totalBytesToRead) {
      deflatedBytes.clear()
      inflaterSource.close()
      this.inflaterSource = null
      this.inflater = null
    }
  }

  @Throws(IOException::class)
  override fun close() {
    inflaterSource?.close()
    inflaterSource = null
    inflater = null
  }

     *
     * @return The global toolchains source or {@code null} if none.
     */
    Source getGlobalToolchainsSource();

    /**
     * Sets the global toolchains source. If both user toolchains and a global toolchains are given, the user toolchains
     * take precedence.
     *
     * @param globalToolchainsSource The global toolchains source, may be {@code null} to disable global toolchains.

 * whose next element can always be derived from the previous element. Null elements are not
 * supported, nor is the {@link #remove()} method.
 *
 * <p>Example:
 *
 * {@snippet :
 * Iterator<Integer> powersOfTwo =
 *     new AbstractSequentialIterator<Integer>(1) {
 *       protected Integer computeNext(Integer previous) {
 *         return (previous == 1 << 30) ? null : previous * 2;
 *       }
 *     };
 * }
 *

        this.open = false;
        if (this.input != null) {
            this.input.close();
            this.input = null;
        }

        if (this.output != null) {
            this.output.close();
            this.output = null;
        }

        try {
            if (wasOpen) {
                this.handle.close();
            } else if (this.handle != null) {
                this.handle.release();

            assertNotNull("Response should not be null", result);
            assertEquals(200, result.getHttpStatusCode());
        } catch (Exception e) {
            fail("Should not throw exception: " + e.getMessage());
        }

        // Test without timeout (null accessTimeout)
        client.setAccessTimeout(null);
        try {

     * @return the normalized content, or empty string if content is null
     */
    public String getContent(final CrawlingConfig crawlingConfig, final ResponseData responseData, final String content,
            final Map<String, Object> dataMap) {
        if (content == null) {
            return StringUtil.EMPTY; // empty
        }

        if (crawlingConfig != null) {

        MavenProject prj = getMavenProject(requireNonNull(project, "project" + " cannot be null"));
        prj.addSourceRoot(
                requireNonNull(scope, "scope" + " cannot be null"),
                requireNonNull(language, "language" + " cannot be null"),
                requireNonNull(directory, "directory" + " cannot be null"));
    }

    @Override
    @Nonnull