WebSocketConfigurer and @Scheduled() are not work well in an application

Question

I can either use websocket that configure with WebSocketConfigurer or use @Scheduled() to schedule task without any problem.

However, java does not compile when i use both of them.

@Scheduled() annotation may crash with org.springframework.web.socket.config.annotation.WebSocketConfigurationSupport$NoOpScheduler.scheduleAtFixedRate()

java.lang.IllegalStateException: Unexpected use of scheduler.
at org.springframework.web.socket.config.annotation.WebSocketConfigurationSupport$NoOpScheduler.scheduleAtFixedRate(WebSocketConfigurationSupport.java:123)
at org.springframework.scheduling.config.ScheduledTaskRegistrar.scheduleFixedRateTask(ScheduledTaskRegistrar.java:462)
at org.springframework.scheduling.config.ScheduledTaskRegistrar.scheduleFixedRateTask(ScheduledTaskRegistrar.java:436)
at org.springframework.scheduling.config.ScheduledTaskRegistrar.scheduleTasks(ScheduledTaskRegistrar.java:357)
at org.springframework.scheduling.config.ScheduledTaskRegistrar.afterPropertiesSet(ScheduledTaskRegistrar.java:332)
at org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor.finishRegistration(ScheduledAnnotationBeanPostProcessor.java:280)
at org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor.onApplicationEvent(ScheduledAnnotationBeanPostProcessor.java:211)
at org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor.onApplicationEvent(ScheduledAnnotationBeanPostProcessor.java:102)
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:399)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:353)
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:887)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:161)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:552)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:388)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234)
at com.yeadev.JavaSpringBootJARAngularSeed.JavaSpringBootJarAngularSeedApplication.main(JavaSpringBootJarAngularSeedApplication.java:22)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)

source code for WebSocketConfiguration

@Slf4j
@Configuration
@EnableWebSocket
public class WebSocketConfiguration implements WebSocketConfigurer {
    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        // added end point,
        // eg. ws://localhost:8080/ws

        // added WebSocketHandler to /ws
        registry.addHandler(new WebSocketHandler(),"/ws");
        log.info("added handler for WebSocket.");
    }
}

source code for ScheduledTasks

@Slf4j
@Component
public class ScheduledTasks {


    private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");

    // @Scheduled()  annotation can not use with WebSocketConfigurer
    @Scheduled(fixedRate=1000)
    public void reportCurrentTime() {
        log.info("The time is now {}", dateFormat.format(new Date()));
    }
}

i use Spring Boot 2.0.0.RELEASE

Answer 1

I ran into the same issue today. It looks as if like Spring web socket creates its own taskScheduler bean which doesn't implement any of the normal operations - it just throws IllegalStateException. This bean is then used for all @Scheduled methods. I was able to resolve this by explicitly creating a task scheduler bean in my ApplicationConfig:

@Bean
public TaskScheduler taskScheduler() {
    ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
    taskScheduler.setPoolSize(10);
    taskScheduler.initialize();
    return taskScheduler;
}