Whereas the MessageHandler interface provides the foundation for many of the components that enable non-invasive invocation of your application code from the messaging system, sometimes it is necessary to invoke the messaging system from your application code. Spring Integration provides a RequestReplyTemplate that supports a variety of request-reply scenarios. For example, it is possible to send a request and wait for a reply.

RequestReplyTemplate template = new RequestReplyTemplate(requestChannel);
Message reply = template.request(new StringMessage("test"));

In that example, a temporary anonymous channel would be used internally by the template. However, the 'replyChannel' may be configured explicitly in which case the template will manage the reply correlation.

RequestReplyTemplate template = new RequestReplyTemplate(requestChannel);
template.setReplyChannel(replyChannel);
Message reply = template.request(new StringMessage("test"));