Can you name the main primitives and tools provided in the java.util.concurrent package for organizing multithreaded execution?

The java.util.concurrent package contains several primitives and tools for organizing multithreaded execution:

• Executor and ExecutorService — interfaces for managing thread pools and asynchronous task execution.
• Future and CompletableFuture — for obtaining the result of asynchronous computations.
• CountDownLatch — allows one or more threads to wait until other threads complete certain actions.
• CyclicBarrier — synchronizes multiple threads, making them wait for each other.
• Semaphore — limits the number of threads that can access a resource simultaneously.
• ReentrantLock — an advanced locking mechanism with the ability to attempt lock acquisition and timeout.
• Concurrent Collections (e.g., ConcurrentHashMap, CopyOnWriteArrayList) — thread-safe collections.
• Atomic Variables (AtomicInteger, AtomicLong, etc.) — for atomic operations on variables without using locks.

Example of using ExecutorService:

ExecutorService executor = Executors.newFixedThreadPool(2);
executor.submit(() -> {
    System.out.println("Task executed in a separate thread");
});
executor.shutdown();