By default Java CAPS uses the Java Message Service infrastructure as its underlying messaging layer. Occasionally there is a requirement or a temptation to develop synchronous service, for example invoked as web services or as HTTP Request/Response services, that invoke some back-end component over JMS. In request/response scenarios the response must be delivered by the component which received the request, a JCD or a BP. If the request is passed to the nback-end infrastructure through a JMS Queue or Topic there arises an issue of getting the response back to the same instance of the JCD or a BP that sent the original request. The attached extract, JMS RequestReply, from an early draft of the “Java CAPS Basics – Implementing Common EAI Patterns“, discusses and illustrates how the JMS RequestReply() method of the JMS OTD can be used to implement this kind of functionality.