* Stops background processing and waits for threads to complete.
     */
    @PreDestroy
    public void destroy() {
        generating = false;
        thumbnailQueueThread.interrupt();
        try {
            thumbnailQueueThread.join(10000);
        } catch (final InterruptedException e) {
            logger.warn("Thumbnail thread timed out.", e);
        }
        generatorList.forEach(g -> {

    threadPool.shutdown();
    threadPool.awaitTermination(300, SECONDS);
  }

  /**
   * Calls get() repeatedly from many different threads, and tests that all of the removed entries
   * (removed because of size limits or expiration) trigger appropriate removal notifications.
   */
  @J2ktIncompatible
  @GwtIncompatible // QueuingRemovalListener

    threadPool.shutdown();
    threadPool.awaitTermination(300, SECONDS);
  }

  /**
   * Calls get() repeatedly from many different threads, and tests that all of the removed entries
   * (removed because of size limits or expiration) trigger appropriate removal notifications.
   */
  @J2ktIncompatible
  @GwtIncompatible // QueuingRemovalListener

   * longer, since an iteration across all row keys occurs.
   *
   * <p>Note that this implementation is not synchronized. If multiple threads access this table
   * concurrently and one of the threads modifies the table, it must be synchronized externally.
   *
   * <p>The table is serializable if {@code backingMap}, {@code factory}, the maps generated by

  @Footprint(exclude = {Runnable.class, Executor.class, Thread.class, Exception.class})
  public Object measureSize() {
    for (Thread thread : blockedThreads) {
      thread.interrupt();
    }
    blockedThreads.clear();
    Facade<Object> f = impl.newFacade();
    for (int i = 0; i < numThreads; i++) {
      Thread thread =
          new Thread() {
            @Override
            public void run() {

    // isn't currently executing this task.
    Runnable currentRunner = get();
    if (currentRunner instanceof Thread) {
      Blocker blocker = new Blocker(this);
      blocker.setOwner(Thread.currentThread());
      if (compareAndSet(currentRunner, blocker)) {
        // Thread.interrupt can throw arbitrary exceptions due to the nio InterruptibleChannel API

    Stopwatch stopwatch = Stopwatch.createStarted();
    Thread thread = new Thread(new JoinTarget(15));
    thread.start();
    thread.join();
    assertFalse(thread.isAlive());

    joinUninterruptibly(thread);
    joinUninterruptibly(thread, 0, MILLISECONDS);
    joinUninterruptibly(thread, -42, MILLISECONDS);
    joinUninterruptibly(thread, LONG_DELAY_MS, MILLISECONDS);

    /** The thread being monitored. */
    protected Thread runningThread;

    /** Flag indicating if the thread is still running. */
    protected AtomicBoolean running = new AtomicBoolean();

    /**
     * Constructs an AccessTimeoutTarget with the specified thread.
     * @param thread The thread to monitor.
     */
    public AccessTimeoutTarget(final Thread thread) {
        runningThread = thread;

    client,
    suggester.settings(),
    "content-index",        // source index
    "document"             // document type
);

suggester.indexer()
    .indexFromDocument(reader, 2, 100)  // threads=2, batch=100
    .getResponse();
```

### Index from Query Logs

```java
import org.codelibs.fess.suggest.index.contents.querylog.QueryLog;

// Add suggestions from search query logs

            logger.warn("Failed to write thread dump: file={}", file, e);
        }
    }

    /**
     * Processes all thread information and sends it to the provided consumer.
     *
     * @param writer the consumer that will handle each line of thread dump output
     */
    public static void processThreadDump(final Consumer<String> writer) {