Spring's @Scheduled error : Only one AsyncAnnotationBeanPostProcessor may exist within the context

Question

I am trying Spring 3\'s @Scheduled annotation . Here is my configuration (app.xml) :

Answer 1

In my case, this was caused by switching versions, thereby in the output file location there are multiple version of jars (and therefore each jar contains a AnnotationBean):

2018-02-19 13:38:44,913 [RMI TCP Connection(3)-127.0.0.1] ERROR org.springframework.web.context.ContextLoader - Context initialization failed
org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: Only one ScheduledAnnotationBeanPostProcessor may exist within the context.
Offending resource: URL [jar:file:/C:/.../lib/xxx-2.0.jar!/META-INF/spring/xxx.xml]

while I'm using 1.0 in this case. So I have to manually delete C:/.../lib/xxx-2.0.jar in this location, and I'm able to see xxx-1.0.jar is also in this directory. After the manual deletion, it works normally.