(Java Message Service) Java-based messaging standard. Part of J2EE, JMS defines a vendor-neutral (but Java-specific) set of programming interfaces for interacting with asynchronous messaging systems. Messages can contain XML documents, Java objects or other formats, and can be sent either to a publish-subscribe list or to a message queue (the two main forms of application messaging). JMS is the first standard to provide a reliable foundation for loosely coupled asynchronous messaging within a distributed, service-oriented environment.