Async() is not invoked in a separate thread after upgrading from 1.2.6 to 1.3.3

[WeipingGuo]

Not sure what changed. We have a simple setup. The Kafka task used to be started in its own executor, but after upgrading to 1.3.3 it always runs in the main thread. Anything I missed? Thanks in advance for your suggestions and helps.

`
@configuration
@EnableAutoConfiguration
@EnableAsync
@EnableCaching
@EnableSwagger
public class Application implements CommandLineRunner {

@Autowired
private KafkaConsumerTask kafkaTask;

public static void main(String[] args) {
    new SpringApplicationBuilder(Application.class).web(true).run(args);
}

@Override
public void run(String... args) throws Exception {
    kafkaTask.start();
}

}

@component
public class KafkaConsumerTask {

@Async("kafkaTaskExecutor")
public void start() {
    log.info("starting consumer for topic: " + topic);
    ...
}

@Bean
public ThreadPoolTaskExecutor kafkaTaskExecutor() {
    ThreadPoolTaskExecutor bean = new ThreadPoolTaskExecutor();
    bean.setCorePoolSize(numberThreads);
    bean.setMaxPoolSize(numberThreads * 2);
    bean.setThreadPriority(priority);
    bean.setWaitForTasksToCompleteOnShutdown(true);
    return bean;
}       

}
`

[wilkinsona]

Can you please provide a complete sample app that reproduces the problem?

[WeipingGuo]

Thanks. I created a sample project: https://github.com/WeipingGuo/boot-async

I ran the same code using different spring boot versions. Appears that the @async is broken on 1.3.0 as it works as expected on 1.2.8

1.2.8
2016-03-08 15:07:36.613 INFO 5452 --- [aTaskExecutor-1] wguo.test.KafkaConsumerTask : starting consumer for topic testing

1.3.0
2016-03-08 18:14:20.464 INFO 7680 --- [ main] wguo.test.KafkaConsumerTask : starting consumer for topic testing

1.3.3
2016-03-08 15:08:49.341 INFO 5908 --- [ main] wguo.test.KafkaConsumerTask : starting consumer for topic testing

[snicoll]

Two things:

• You are creating a @Bean from a @Component class. That should be specified in a @Configuration class
• You are injecting the service using field injection in the application class. Because it has to be instantiated quite early, I guess the framework is unable to inject the bean with the async proxy around it

If I move the task executor to the application and I move the CommandLineRunner to an inner class of the app it works.

Having said that, it's sill weird that it works in 1.2.x

[wilkinsona]

It also stops working with 1.2.x if you upgrade Spring Framework to 4.2.5.RELEASE

[wilkinsona]

Running with 4.2.5.RELEASE triggers these log messages:

2016-03-09 09:52:00.916  INFO 48097 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'kafkaConsumerTask' of type [class wguo.test.KafkaConsumerTask] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2016-03-09 09:52:00.917  INFO 48097 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'application' of type [class wguo.test.Application$$EnhancerBySpringCGLIB$$7d48eac9] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2016-03-09 09:52:00.929  INFO 48097 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService  'kafkaTaskExecutor'
2016-03-09 09:52:00.931  INFO 48097 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'kafkaTaskExecutor' of type [class org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)

Something's changed in Spring Framework 4.2.x that means that something is triggering very early instantiation of the KafkaTaskExecutor bean, so early that it isn't eligible for bean post-processing which prevents the proxy for async method execution from being created.

[wilkinsona]

I can recreate this with pure Spring Framework so this isn't a problem with Spring Boot itself. I have opened SPR-14030 to track the problem.

[WeipingGuo]

Thanks for looking into it. @snicoll You are right. My bean creation was wrong, somehow it worked before.

I moved the ThreadPoolTaskExecutor to its own class with @configuration. Now it works as charm.

I guess it is not bug in Spring rather than my programming error.