Have you worked with multithreading? What did you use?

Yes, I have worked with multithreading in Java. For implementation, I used:

• Classes from the java.util.concurrent package — for example, ExecutorService to manage thread pools.
• Synchronization using the synchronized keyword and ReentrantLock classes to protect shared resources.
• Concurrent Collections — such as ConcurrentHashMap, to avoid issues with concurrent access.
• Future and Callable for asynchronous task execution with the ability to obtain results.

Example of creating a thread pool and running a task:

ExecutorService executor = Executors.newFixedThreadPool(3);
executor.submit(() -> {
    // task code
    System.out.println("Executing in a separate thread");
});
executor.shutdown();

Using these tools allows for efficient and safe multithreading in Java.