Spring @Async Not Working

Question

An @Async method in a @Service-annotated class is not being called asynchronously - it\'s blocking the thread.

I\'ve got

Answer 1

Jiří Vypědřík's answer solved my problem. Specifically,

2. Check if your method annotated with @Async is public.

Another useful information from Spring tutorials https://spring.io/guides/gs/async-method/:

Creating a local instance of the FacebookLookupService class does NOT allow the findPage method to run asynchronously. It must be created inside a @Configuration class or picked up by @ComponentScan.

What this means is that if you had a static method Foo.bar(), calling it in that manner wouldn't execute it in async, even if it was annotated with @Async. You'll have to annotate Foo with @Component, and in the calling class get an @Autowired instance of Foo.

Ie, if you have a annotated method bar in class Foo:

@Component
class Foo { 
   @Async
   public static void bar(){ /* ... */ }

   @Async
   public void bar2(){ /* ... */ }
}

An in your caller class:

class Test {

  @Autowired Foo foo;

  public test(){
     Foo.bar(); // Not async
     foo.bar(); // Not async
     foo.bar2(); // Async
  }

}

Edit: Seems like calling it statically also doesn't execute it in async.

Hope this helps.

Answer 2

Firstly make your .xml config looks like:

<task:scheduler id="myScheduler" pool-size="10" />
<task:executor id="myExecutor" pool-size="10" />
<task:annotation-driven executor="myExecutor" scheduler="myScheduler" proxy-target-class="true" />

(Yes, scheduler count and executor thread pool size is configurable)

Or just use default:

<!-- enable task annotation to support @Async, @Scheduled, ... -->
<task:annotation-driven />

Secondly make sure @Async methods are public.

Answer 3

For me the solution was to add @EnableAsync on my @Configuration annotated class:

@Configuration
@ComponentScan("bla.package")
@EnableAsync
public class BlaConfiguration {

}

Now the class in package bla.package which has @Async annotated methods can really have them called asynchronously.

Answer 4

write a independent Spring configuration for asynchronous bean.
for example:

@Configuration
@ComponentScan(basePackages="xxxxxxxxxxxxxxxxxxxxx")
@EnableAsync
public class AsyncConfig {

    /**
     *  used by  asynchronous event listener.
     * @return
     */
    @Bean(name = "asynchronousListenerExecutor")
    public Executor createAsynchronousListenerExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setMaxPoolSize(100);
        executor.initialize();
        return executor;
    }
}

I overcome this problem with this situation.

Answer 5

You need 3 lines of code for Async to work

1. in applicationContext.xml
2. At class level @EnableAsync
3. @Async at method level

@Service @EnableAsync public myClass {

@Async public void myMethod(){

}