Spring Cloud Stream #SendTo Annotation not working - spring

Question

I'm using Spring Cloud Stream with Spring Boot. My application is very simple:
ExampleService.class:
#EnableBinding(Processor1.class)
#Service
public class ExampleService {
#StreamListener(Processor1.INPUT)
#SendTo(Processor1.OUTPUT)
public String dequeue(String message){
System.out.println("New message: " + message);
return message;
}
#SendTo(Processor1.OUTPUT)
public String queue(String message){
return message;
}
}
Procesor1.class:
public interface Processor1 {
String INPUT = "input1";
String OUTPUT = "output1";
#Input(Processor1.INPUT)
SubscribableChannel input1();
#Output(Processor1.OUTPUT)
MessageChannel output1();
}
application.properties:
spring.cloud.stream.bindings.input1.destination=test_input
spring.cloud.stream.bindings.input1.group=test_group
spring.cloud.stream.bindings.input1.binder=binder1
spring.cloud.stream.bindings.output1.destination=test_output
spring.cloud.stream.bindings.output1.binder=binder1
spring.cloud.stream.binders.binder1.type=rabbit
spring.cloud.stream.binders.binder1.environment.spring.rabbitmq.host=localhost
Scenarios:
1) When I push a message in 'test_input.test_group' queue, message is correctly printed and correctly sent to 'test_output' exchange. So ExampleService::dequeue works well.
2) When I invoke ExampleService::queue method (from outside the class, in a test), message is never sent to 'test_output' exchange.
I'm working with Spring Boot 2.0.6.RELEASE and Spring Cloud Stream 2.0.2.RELEASE.
Anybody knows why scenario 2) is not working? Thanks in advance.

Answer 1

What leads you to believe that #SendTo on its own is supported? #SendTo is a secondary annotation used by many projects, not just Spring Cloud Stream; as far as I know, there is nothing that will look for it on its own.
Try Spring Integration's #Publisher annotation instead (with #EnablePublisher).
EDIT
To force proxying with CGLIB instead of a JDK proxy, you can do this...
#Bean
public static BeanFactoryPostProcessor bfpp() {
return bf -> {
bf.getBean(IntegrationContextUtils.PUBLISHER_ANNOTATION_POSTPROCESSOR_NAME,
PublisherAnnotationBeanPostProcessor.class).setProxyTargetClass(true);
};
}