WebSocketConfigurer and #Scheduled() are not work well in an application - spring

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;
}