How can multithreading be implemented in a high-load service that performs many similar heavy tasks?

To implement multithreading in a high-load service with many similar heavy tasks in Java, a thread pool (ThreadPoolExecutor) from the java.util.concurrent package is usually used.

Main steps:

• Create a fixed or dynamic thread pool to limit the number of concurrently working threads and avoid excessive load on the system.
• Place tasks in a queue (e.g., LinkedBlockingQueue).
• The thread pool will take tasks from the queue and execute them in parallel.

Example:

ExecutorService executor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());

for (Task task : tasks) {
    executor.submit(() -> {
        // heavy task
        task.execute();
    });
}

executor.shutdown();
executor.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);

This approach allows efficient use of CPU resources, managing the number of threads, and processing a large number of tasks in parallel.

For more complex scenarios, you can use ForkJoinPool or reactive libraries (e.g., Reactor, RxJava).