codes

[siddharthrgade21-a11y]

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.*;

public class AdvancedConcurrencyExample {

public static void main(String[] args) {
    // Create a thread pool with 3 threads
    ExecutorService executorService = Executors.newFixedThreadPool(3);
    List<Future<Long>> futures = new ArrayList<>();

    System.out.println("Submitting tasks...");

    // Submit several complex calculation tasks
    for (int i = 1; i <= 5; i++) {
        Callable<Long> task = new FactorialTask(i);
        Future<Long> future = executorService.submit(task);
        futures.add(future);
    }

    // Retrieve the results using futures
    for (Future<Long> future : futures) {
        try {
            // get() waits if the task is not complete
            System.out.println("Task result: " + future.get());
        } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
        }
    }

    // Shut down the executor service
    executorService.shutdown();
    System.out.println("All tasks finished and executor shut down.");
}

}

// A complex task that calculates the factorial of a number
class FactorialTask implements Callable {
private final int number;

public FactorialTask(int number) {
    this.number = number;
}

@Override
public Long call() throws Exception {
    if (number < 0) {
        throw new IllegalArgumentException("Number must be non-negative");
    }
    long result = 1;
    for (int i = 1; i <= number; i++) {
        result *= i;
        // Simulate some hard work
        Thread.sleep(100); 
    }
    System.out.println("Calculated factorial of " + number + " in " + Thread.currentThread().getName());
    return result;
}

}