Can you explain the purpose and main features of the java.util.concurrent package in Java?

The java.util.concurrent package is designed to simplify the development of multithreaded applications in Java. It provides high-level utilities and data structures that help manage threads, synchronization, and concurrent access to resources.

Main features:

• Executor Framework — managing thread pools and asynchronous task execution through interfaces Executor, ExecutorService.
• Synchronizers — classes for thread coordination, such as CountDownLatch, CyclicBarrier, Semaphore, Exchanger.
• Blocking Queues — queues supporting thread-safe addition and removal of elements, such as LinkedBlockingQueue, ArrayBlockingQueue.
• Atomic Variables — classes from the java.util.concurrent.atomic package for non-blocking value updates.
• State Management Classes — for example, Future and Callable for working with asynchronous task results.

Example of using ExecutorService:

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