Java 17 - Controlling Thread Pool Sizes Dynamically with Executors in Spring Boot
I'm migrating some code and I'm working on a personal project and I'm having a hard time understanding I'm currently working on a Spring Boot application using Java 17, and I'm working with an scenario where I need to dynamically adjust the size of a thread pool used by an `ExecutorService`... I originally configured the thread pool using `ThreadPoolTaskExecutor`, but it seems that setting the core and max pool sizes at runtime isn't straightforward. Here's how I initially set it up in my configuration class: ```java import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor; @Configuration public class ThreadPoolConfig { @Bean public ThreadPoolTaskExecutor taskExecutor() { ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor(); executor.setCorePoolSize(5); executor.setMaxPoolSize(10); executor.setQueueCapacity(25); executor.initialize(); return executor; } } ``` The application works fine, but I need to allow the user to adjust the pool sizes through a REST API. When I try to update the pool size using the `setCorePoolSize` and `setMaxPoolSize` methods on the `ThreadPoolTaskExecutor`, it appears to have no effect. I call these methods as follows: ```java @Autowired private ThreadPoolTaskExecutor taskExecutor; @PostMapping("/update-pool-size") public ResponseEntity<String> updatePoolSize(@RequestParam int coreSize, @RequestParam int maxSize) { taskExecutor.setCorePoolSize(coreSize); taskExecutor.setMaxPoolSize(maxSize); return ResponseEntity.ok("Pool sizes updated"); } ``` However, the current active threads do not change, and the application does not seem to utilize the new sizes. I also checked the logs for any warnings or errors, but nothing stands out. Is there a specific way I should be updating the thread pool parameters, or do I need to manage the thread pool lifecycle differently? Any insights would be appreciated! The project is a desktop app built with Java. Is there a simpler solution I'm overlooking? This is my first time working with Java 3.10. I'd love to hear your thoughts on this. I've been using Java for about a year now.