List<Thread> threads = new ArrayList<>(numThreads);
    final List<Throwable> exceptions = new ArrayList<>(numThreads);
    for (int i = 0; i < numThreads; i++) {
      Thread thread = new Thread(task);
      thread.setUncaughtExceptionHandler(
          new UncaughtExceptionHandler() {
            @Override
            public void uncaughtException(Thread t, Throwable e) {

    assertFalse(future.isDone());
    assertFalse(future.isCancelled());

    CountDownLatch successLatch = new CountDownLatch(1);

    // Run cancellation in a separate thread as an extra thread-safety test.
    new Thread(
            () -> {
              assertThrows(CancellationException.class, future::get);
              successLatch.countDown();
            })
        .start();

    List<Thread> threads = new ArrayList<>(numThreads);
    final List<Throwable> exceptions = new ArrayList<>(numThreads);
    for (int i = 0; i < numThreads; i++) {
      Thread thread = new Thread(task);
      thread.setUncaughtExceptionHandler(
          new UncaughtExceptionHandler() {
            @Override
            public void uncaughtException(Thread t, Throwable e) {

            });
    assertFalse(task.isDone());
    Thread thread =
        new Thread(
            new Runnable() {
              @Override
              public void run() {
                try {
                  task.run();
                } finally {
                  exitLatch.countDown();
                }
              }
            });
    thread.start();
    enterLatch.await();

  /**
   * 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>
   *

        logger.log(
            Level.INFO, "Failed to create a thread without inherited thread-local values", t);
      }
    }
    if (thread == null) {
      thread = new Thread((ThreadGroup) null, finalizer, threadName);
    }
    thread.setDaemon(true);

    try {
      if (inheritableThreadLocals != null) {
        inheritableThreadLocals.set(thread, null);
      }
    } catch (Throwable t) {
      logger.log(

                }
                return toReturn;
              }
            }
            return super.loadClass(name);
          }
        };
    oldClassLoader = Thread.currentThread().getContextClassLoader();
    Thread.currentThread().setContextClassLoader(classReloader);

    oldSecurityManager = System.getSecurityManager();
    /*

        } else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {
                      holder.count++;
                      return Thread.currentThread().getStackTrace().length;

        } else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {
                      holder.count++;
                      return Thread.currentThread().getStackTrace().length;

        return instance;
    }

    /**
     * 処理を開始します。
     */
    public synchronized void start() {
        if (thread == null) {
            thread = new Thread(this, "CoreLib-TimeoutManager");
            thread.setDaemon(true);
            thread.start();
            if (logger.isDebugEnabled()) {
                logger.debug("TimeoutManager started.");
            }
        }
    }