* {@link Map} specified in the {@link Table} interface.
 *
 * <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>See the Guava User Guide article on <a href=

 * {@link Map} specified in the {@link Table} interface.
 *
 * <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>See the Guava User Guide article on <a href=

    protected long crawlingExecutionInterval = Constants.DEFAULT_CRAWLING_EXECUTION_INTERVAL;

    /**
     * Thread priority for index updater operations.
     */
    protected int indexUpdaterPriority = Thread.MAX_PRIORITY;

    /**
     * Thread priority for crawler operations.
     */
    protected int crawlerPriority = Thread.NORM_PRIORITY;

    /**
     * Synchronized list of active crawlers.
     */

     */
    protected ExecutorService newFixedThreadPool(final int nThreads) {
        if (logger.isDebugEnabled()) {
            logger.debug("Initialized executor thread pool: size={}", nThreads);
        }
        return new ThreadPoolExecutor(nThreads, nThreads, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<>(nThreads),
                new ThreadPoolExecutor.CallerRunsPolicy());
    }

    @Override

 * possibly run in another thread. That cause should itself be an {@code Error}; if not, use {@code
 * ExecutionException} or {@link UncheckedExecutionException}. This allows the client code to
 * continue to distinguish between exceptions and errors, even when they come from other threads.
 *
 * @author Chris Povirk
 * @since 10.0
 */
@GwtCompatible

  /**
   * Returns an exception handler that exits the system. This is particularly useful for the main
   * thread, which may start up other, non-daemon threads, but fail to fully initialize the
   * application successfully.
   *
   * <p>Example usage:
   *
   * <pre>
   * public static void main(String[] args) {
   *   Thread.currentThread().setUncaughtExceptionHandler(UncaughtExceptionHandlers.systemExit());
   *   ...
   * </pre>
   *

 * due to eviction resulting from timed expiration, exceeding a maximum size, or garbage collection.
 *
 * <p>An instance may be called concurrently by multiple threads to process different entries.
 * Implementations of this interface should avoid performing blocking calls or synchronizing on
 * shared resources.
 *

@defaultMessage this method needs special permission
java.lang.Thread#getAllStackTraces()

@defaultMessage Stopping threads explicitly leads to inconsistent states. Use interrupt() instead.
java.lang.Thread#stop()
# uncomment when https://github.com/elastic/elasticsearch/issues/31715 is fixed
# java.lang.Thread#stop(java.lang.Throwable)

@defaultMessage Please do not terminate the application

            });
    assertFalse(task.isDone());
    Thread thread =
        new Thread(
            () -> {
              try {
                task.run();
              } finally {
                exitLatch.countDown();
              }
            },
            "Custom thread name");
    thread.start();
    enterLatch.await();
    assertFalse(task.isDone());

        fesenClient = new FesenClient();
        mockClient = mock(Client.class);
        fesenClient.client = mockClient;
    }

    /**
     * Test: Thread-safe listener management using CopyOnWriteArrayList
     * Verifies that multiple threads can safely add listeners concurrently
     */
    @Test
    public void testThreadSafeListenerManagement() throws Exception {
        final int numThreads = 10;