Default Poller for MessageEndpoint?

What is the default Poller when just setting up a @MessageEndpoint with a single @ServiceActivator?

@MessageEndpoint
public class MyEndpoint {
    @ServiceActivator(inputChannel = "myChannel") //OK without poller
    public void chan() {
    }
}

1. Question: which poller does this service activator use?

Then, when I add additional MessageEndpoint, suddenly a poller is required:

@MessageEndpoint
public class MyEndpoint2 {
    @ServiceActivator(inputChannel = "myChannel2") //NOK without poller!
    public void chan() {
    }
}

Result:

Caused by: java.lang.IllegalArgumentException: No poller has been defined for Annotation-based endpoint, and no default poller is available within the context.
    at org.springframework.util.Assert.notNull(Assert.java:112)
    at org.springframework.integration.config.annotation.AbstractMethodAnnotationPostProcessor.configurePollingEndpoint(AbstractMethodAnnotationPostProcessor.java:321)
    at org.springframework.integration.config.annotation.AbstractMethodAnnotationPostProcessor.doCreateEndpoint(AbstractMethodAnnotationPostProcessor.java:250)
    at org.springframework.integration.config.annotation.AbstractMethodAnnotationPostProcessor.createEndpoint(AbstractMethodAnnotationPostProcessor.java:241)
    at org.springframework.integration.config.annotation.AbstractMethodAnnotationPostProcessor.postProcess(AbstractMethodAnnotationPostProcessor.java:160)
    at org.springframework.integration.config.annotation.MessagingAnnotationPostProcessor$1.doWith(MessagingAnnotationPostProcessor.java:151)
    at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:496)