Or you can create a few lines of normal Java code using the ScheduledExecutor. Takes a lot less space and is much better understandable. The whole annotation thing is making code hard to understand.

ex-spring enthusiast.

yeah!!!
I Love Spring 3

This all looks great, but what about support for a clustered configuration where you only want one of the jobs in the cluster to fire?

I would agree, that until my last client the Spring 3.0 implementation of Tasks would have been more than sufficient and saved me a ton of time. It would be nice to see it extended to support clustering via some sort of Quartz annotation or configuration mechanism so you get the best of both worlds.

My main motivation for using Quartz in addition to the TaskExecutor is that when using Quartz, I have the ability to have my schedules 'filtered' by a Calendar, so that I can exclude blocks of time. I generally use Quartz Calendars in combination with CronTriggers to express something like "every hour on non-holidays during working hours". Would love a similar functionality independent of Quartz.

I've played with this new scheduling support. However, after switching to this new style, and using "task:scheduled-tasks" element in my application context file, I'm no longer able to shut down Tomcat on which application is deployed. I have to kill tomcat process. I guess this element creates some non-daemon thread which will stop VM from exiting.
Looks definitely like a bug.

Ok, I described it here: http://forum.springsource.org/showthread.php?p=280269#post280269

Hi Mark,

I may have found a potential bug when using annotation based task scheduling and in particular:

@Scheduled(cron="* 10/1 * * * * ?")

After I have done a bit more testing if I find it is still an issue should I raise it on JIRA?

Ok, this might be a very basic question but what is the best way to externalize values like the fixedDelay here?:

@Scheduled(fixedDelay = 30000)

I'd like to be able to define/override that value with a properties file or command line argument without having to change the actual code.

1 for cluster support

The task:annotation-driven conflicts with the annotation driven JMX support. When i add @Async () to a JMX annotated class (e.g. @ManagedResource(..)) i get following startup exception:
MetadataMBeanInfoAssembler does not support JDK dynamic proxies – export the target beans directly or use CGLIB proxies instead

I guess the conflict is due to the interface-based AOP proxies used to instrument the @Async classes. According to the spring doc (http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/jmx.html#jmx-context-mbeanexport):

"Do not use interface-based AOP proxies in combination with autodetection of JMX annotations in your bean classes. Interface-based proxies 'hide' the target class, which also hides the JMX managed resource annotations. Hence, use target-class proxies in that case: through setting the 'proxy-target-class' flag on , , etc. Otherwise, your JMX beans might be silently ignored at startup…"

Is there a known workaround for this?

Cheers,Chris

Michal, perhaps the scheduler-not-being-destroyed condition would contribute to the issue but the root cause seems to be an interference between to the aop proxies used in the task/scheduler and the @ManagedResources implementations. In result you may not able to use together Task and JMX annotation in the same class.

Mark, I think you could update the last XML snippet of this article, so that task:scheduled-tasks element has scheduler="…" attribute. The Spring forum thread I mentioned above, suggested that lack of this attribute was the reason why Tomcat couldn't shut down properly (probably I had copied the snipped from this article to my app).

If there is a lot of request invoking the async method,it will cause OutOfMemoryError.

How to control the thread number in the thread pool?Tks.

}

In the code:
@Async
@scheduled(cron="* 1/10 * * *")
myMethod(){}

Does this cause any problems..?? This seems to be working for me.

Sorry… I tried to post some raw XML code… here's the "entitized" one:

<task:scheduled-tasks scheduler="scheduler">
<task:scheduled ref="processor" method="process" fixed-rate="10000" />
</task:scheduled-tasks>

(erase it if you want)

Getting the below exception while trying with @Async with the below code. Appreciate any help.

package springservice;
import java.util.*;
import org.springframework.beans.factory.annotation.*;
import org.springframework.scheduling.annotation.*;
import org.springframework.context.support.*;
import org.springframework.context.annotation.*;
import org.springframework.stereotype.*;

@Service
public class SpringScheduler {

@Autowired
private Worker worker;

@Scheduled(fixedDelay=10000)
public void run()
{
System.out.println(" run called ");
worker.work();
}

public static void main(String a[])
{
new ClassPathXmlApplicationContext("spring.xml");
}
}

interface WorkerInterface
{
public void work();
}

@Component
class Worker implements WorkerInterface
{
@Async
public void work()
{
System.out.println(new Date() "::" Thread.currentThread().getName());
}
}

[/java] Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'springScheduler': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private springservice.Worker springservice.SpringScheduler.worker; nested exception is java.lang.IllegalArgumentException: Can not set springservice.Worker field springservice.SpringScheduler.worker to springservice.$Proxy11
     [java]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:285)

[/java] 	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1074)
     [java]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)

[/java] 	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
     [java]

at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)

[/java] 	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
     [java]

at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)

[/java] 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190)
     [java]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:580)

[/java] 	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:895)
     [java]

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:425)

[/java] 	at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:139)
     [java]

at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:83)

[/java] 	at springservice.SpringScheduler.main(SpringScheduler.java:24)
     [java]

Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private springservice.Worker springservice.SpringScheduler.worker; nested exception is java.lang.IllegalArgumentException: Can not set springservice.Worker field springservice.SpringScheduler.worker to springservice.$Proxy11

[/java] 	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:502)
     [java]

at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:84)

[/java] 	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:282)
     [java]

… 13 more

[/java] Caused by: java.lang.IllegalArgumentException: Can not set springservice.Worker field springservice.SpringScheduler.worker to springservice.$Proxy11
     [java]

at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:146)

[/java] 	at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:150)
     [java]

at sun.reflect.UnsafeObjectFieldAccessorImpl.set(UnsafeObjectFieldAccessorImpl.java:63)

[/java] 	at java.lang.reflect.Field.set(Field.java:657)
     [java]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:498)

[/java] 	... 15 more
     [java]

Java Result: 1
BUILD SUCCESSFUL
Total time: 1 second

Yes, thats done the trick.

Mark,
Great post!
One question: Could you explain why AtomicInteger is needed in the ScheduledProcessor?
As I see it a simple int would also be ok because the process method is executed in a single thread.

I have a question.
If I use @Async, How to config to create the daemon thread ?

@Mark, truly a Great writeup.

@Dave, Is there a way by which we can incorporate these @Async features to replace AsyncItemProcessor & AsyncItemWriter as a part of Spring Batch Integration

Hi All,

In the above given example By – Mark Fisher. there is a main() method. In java web application using ecplise and spring as framework how is it possible to execute a class with main() method. plsss sum1 help me on this…..m really in bad need of this example.

@vikas, the namespace is http://www.springframework.org/schema/task and its location is http://www.springframework.org/schema/task/spring-task-3.0.xsd

Great Job. Could you please give some clue for how to download the whole project from subversion? I tried eclipse subclipse and TortoiseSVN, and got error. Thanks.

Excellent notes! My requirement is that a User should be able to schedule new jobs through a Web GUI. All the examples I saw so far related to Spring Batch with Quartz or Spring Task Scheduler refer to having "static" or Pre-configured jobs in the XML or in Java code, which means that adding new jobs would need a re-deployment of the web-application. Can't we schedule jobs on the fly and make them persistent to survive a server restart?