The Java Message Service (JMS) support included with SAP Web Application Server 6.20 and higher allows distributed business applications to be integrated in a reliable, flexible, and vendor-independent way. Using JMS, Java programs running on disparate systems exchange messages through a central messaging server, rather than a direct connection to one another. This article shows you how to leverage this architecture to enhance your JMS-based applications by using asynchronous message delivery to streamline code and improve scalability, and using message selectors to reduce memory consumption and boost performance. It also points out some pitfalls to help you avoid common trouble spots.