/**
   * Returns the {@link Executor} that will be used to run this service. Subclasses may override
   * this method to use a custom {@link Executor}, which may configure its worker thread with a
   * specific name, thread group or priority. The returned executor's {@link
   * Executor#execute(Runnable) execute()} method is called when this service is started and

import com.google.common.annotations.GwtCompatible;
import java.util.concurrent.Executor;

/**
 * An {@link Executor} that runs each task in the thread that invokes {@link Executor#execute
 * execute}.
 */
@GwtCompatible
enum DirectExecutor implements Executor {
  INSTANCE;

  @Override
  public void execute(Runnable command) {
    command.run();
  }

  @Override
  public String toString() {

        int iterations = 1000;
        ExecutorService executor = Executors.newFixedThreadPool(2);
        CountDownLatch endLatch = new CountDownLatch(2);
        AtomicInteger successCount = new AtomicInteger(0);
        List<Exception> exceptions = Collections.synchronizedList(new ArrayList<>());

        // Thread 1: Continuously adds trees
        executor.submit(() -> {
            try {

      .build()

  @After
  fun tearDown() {
    engine.shutdown()
    cacheDir.deleteRecursively()
  }

  @Test
  fun get() {
    val executor = Executors.newCachedThreadPool()

    val completableFuture = execute(engine, executor, "https://google.com/robots.txt")

    try {
      val response = completableFuture.get(10, TimeUnit.SECONDS)

      assertEquals(200, response.code)

   */
  public <T extends @Nullable Object> ListenableFuture<T> submitAsync(
      AsyncCallable<T> callable, Executor executor) {
    checkNotNull(callable);
    checkNotNull(executor);
    TaskNonReentrantExecutor taskExecutor = new TaskNonReentrantExecutor(executor, this);
    AsyncCallable<T> task =
        new AsyncCallable<T>() {
          @Override

            processor.setSearcher(new TestSearcher(100));
            processor.init();

            final ExecutorService executor = Executors.newFixedThreadPool(numThreads);
            try {
                for (int i = 0; i < numThreads; i++) {
                    final int threadId = i;
                    executor.submit(() -> {
                        try {
                            startLatch.await(); // Wait for all threads to be ready

    List<Future<?>> results = new ArrayList<>();
    Runnable[] manualExecutorTask = new Runnable[1];
    Executor manualExecutor =
        new Executor() {
          @Override
          public void execute(Runnable task) {
            manualExecutorTask[0] = task;
          }
        };

    results.add(serializer.submit(Callables.returning(null), manualExecutor));

    // null only for TOMBSTONE
    final @Nullable Executor executor;

    // writes to next are made visible by subsequent CAS's on the listeners field
    @Nullable Listener next;

    Listener(Runnable task, Executor executor) {
      this.task = task;
      this.executor = executor;
    }

    Listener() {
      this.task = null;
      this.executor = null;
    }
  }

                return paramMap.size();
            }
        });

        // Execute first time
        Object result1 = scriptExecutor.execute("modifyEngine", "script1");
        assertEquals(2, result1); // executor + newKey

        // Execute second time - params should be fresh
        Object result2 = scriptExecutor.execute("modifyEngine", "script2");
        assertEquals(2, result2); // Should still be 2, not accumulating

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link ClosingFuture} that exercise {@link
 * ClosingFuture#finishToValueAndCloser(ValueAndCloserConsumer, Executor)}.
 */
@NullUnmarked
@GwtIncompatible
@J2ktIncompatible