👀 Views: 78 💬 Answers: 1 📅 Created: 2025-06-17

java concurrency scheduledexecutorservice java17 Java

I've hit a wall trying to I'm working on a project and hit a roadblock... I'm encountering an issue with the `ScheduledExecutorService` in Java 17 where tasks are not being interrupted as expected when I call the `shutdownNow()` method. I have set up a scheduled task that runs every second and checks for a certain condition to continue processing. When I invoke `shutdownNow()`, I expect all running tasks to cease immediately, but it appears that some tasks continue running for a bit longer than I anticipated. Here's a simplified version of my code: ```java import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; public class ScheduledTaskExample { private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1); public void start() { scheduler.scheduleAtFixedRate(() -> { try { System.out.println("Task is running..."); // Simulating some long-running task Thread.sleep(3000); } catch (InterruptedException e) { System.out.println("Task was interrupted!"); } }, 0, 1, TimeUnit.SECONDS); } public void stop() { System.out.println("Stopping scheduler..."); scheduler.shutdownNow(); } public static void main(String[] args) throws InterruptedException { ScheduledTaskExample example = new ScheduledTaskExample(); example.start(); Thread.sleep(5000); example.stop(); } } ``` In this code, I expect the task to stop immediately when `shutdownNow()` is called. However, even after this call, the output sometimes shows "Task is running..." being printed again. I've verified that the `InterruptedException` is caught, but the task doesn’t seem to stop immediately as I had hoped. I've tried modifying the sleep duration and also adding checks to verify if the thread is interrupted, but it doesn't seem to affect the behavior. It almost seems like the task is prioritizing its execution over the interruption signal. Is there a best practice for ensuring that tasks can be halted more reliably when using a `ScheduledExecutorService`? Any insights or suggestions would be greatly appreciated. This is my first time working with Java 3.9. What would be the recommended way to handle this? I'm developing on Debian with Java.