throws IOException {
    Path parentPath = getParentPath(path);
    if (parentPath == null) {
      throw new FileSystemException(path.toString(), null, "can't delete recursively");
    }

    Collection<IOException> exceptions = null; // created lazily if needed
    try {
      boolean sdsSupported = false;

      if (entry.getKey() == null) {
        tryDrainReferenceQueues();
        return null;
      }
      V value = entry.getValue();
      if (value == null) {
        tryDrainReferenceQueues();
        return null;
      }

      return value;
    }

    /**
     * Performs routine cleanup following a read. Normally cleanup happens during writes, or from

      cachingHashMap.remove(key);
      return null;
    }
  }

  @CanIgnoreReturnValue
  @Override
  public V put(K key, V value) {
    checkNotNull(key);
    checkNotNull(value);
    Timestamped<V> oldValue = cachingHashMap.put(key, new Timestamped<V>(value, ticker));
    if (oldValue == null) {
      return null;
    }

        if( domain == null || username == null ||
                                    ansiHash == null || unicodeHash == null ) {
            throw new IllegalArgumentException( "External credentials cannot be null" );
        }
        this.domain = domain;
        this.username = username;
        this.password = null;
        this.challenge = challenge;
        this.ansiHash = ansiHash;

  private val key: String

  /** Non-null for client web sockets. These can be canceled. */
  internal var call: Call? = null

  /** This task processes the outgoing queues. Call [runWriter] to after enqueueing. */
  private var writerTask: Task? = null

  /** Null until this web socket is connected. Only accessed by the reader thread. */
  private var reader: WebSocketReader? = null

    while (true) {
      AtomicInteger existingCounter = safeGet(countMap, element);
      if (existingCounter == null) {
        existingCounter = countMap.putIfAbsent(element, new AtomicInteger(occurrences));
        if (existingCounter == null) {
          return 0;
        }
        // existingCounter != null: fall through to operate against the existing AtomicInteger
      }

      while (true) {

    assertNull(
        "Throwable from other thread: "
            + (throwable == null ? null : Throwables.getStackTraceAsString(throwable)),
        throwableFromOtherThread.get());
  }

  /**
   * Test for a bug where threads weren't getting signaled when shutdown was called, only when tasks
   * completed.
   */
  public void testDirectExecutorService_awaitTermination_missedSignal() {

	}
	for k, v := range m.Histogram {
		metric.Histogram[k] = v
	}
	return metric
}

// Get - returns cached value always upton the configured TTL,
// once the TTL expires "read()" registered function is called
// to return the new values and updated.
func (g *MetricsGroupV2) Get() (metrics []MetricV2) {
	m, _ := g.metricsCache.Get()
	if len(m) == 0 {
		return []MetricV2{}
	}

      int size = (keyList == null) ? 0 : keyList.count;
      checkPositionIndex(index, size);
      if (index >= (size / 2)) {
        previous = (keyList == null) ? null : keyList.tail;
        nextIndex = size;
        while (index++ < size) {
          previous();
        }
      } else {
        next = (keyList == null) ? null : keyList.head;
        while (index-- > 0) {
          next();

		}
	}

	var (
		name     string
		idx      = strings.Index(str, ",")
		settings = ParseTagSetting(str, ",")
	)

	// optimize match english letters and midline
	// The following code is basically called in for.
	// In order to avoid the performance problems caused by repeated compilation of regular expressions,
	// it only needs to be done once outside, so optimization is done here.