Spring provides a JMS integration framework that simplifies the use of the JMS API and shields the user from differences between the JMS 1.0.2 and 1.1 APIs.

JMS can be roughly divided into two areas of functionality, namely the production and consumption of messages. The JmsTemplate class is used for message production and synchronous message reception. For asynchronous reception similar to J2EE's message-driven bean style, Spring provides a number of message listener containers that are used to create Message-Driven POJOs (MDPs).

Domain Unification

There are two major releases of the JMS specification, 1.0.2 and 1.1.

JMS 1.0.2 defined two types of messaging domains, point-to-point (Queues) and publish/subscribe (Topics). The 1.0.2 API reflected these two messaging domains by providing a parallel class hierarchy for each domain. As a result, a client application became domain specific in its use of the JMS API. JMS 1.1 introduced the concept of domain unification that minimized both the functional differences and client API differences between the two domains. As an example of a functional difference that was removed, if you use a JMS 1.1 provider you can transactionally consume a message from one domain and produce a message on the other using the same Session.

	Note
	The JMS 1.1 specification was released in April 2002 and incorporated as part of J2EE 1.4 in November 2003. As a result, common J2EE 1.3 application servers which are still in widespread use (such as BEA WebLogic 8.1 and IBM WebSphere 5.1) are based on JMS 1.0.2.

The package org.springframework.jms.core provides the core functionality for using JMS. It contains JMS template classes that simplifies the use of the JMS by handling the creation and release of resources, much like the JdbcTemplate does for JDBC. The design principle common to Spring template classes is to provide helper methods to perform common operations and for more sophisticated usage, delegate the essence of the processing task to user implemented callback interfaces. The JMS template follows the same design. The classes offer various convenience methods for the sending of messages, consuming a message synchronously, and exposing the JMS session and message producer to the user.

The package org.springframework.jms.support provides JMSException translation functionality. The translation converts the checked JMSException hierarchy to a mirrored hierarchy of unchecked exceptions. If there are any provider specific subclasses of the checked javax.jms.JMSException, this exception is wrapped in the unchecked UncategorizedJmsException.

The package org.springframework.jms.support.converter provides a MessageConverter abstraction to convert between Java objects and JMS messages.

The package org.springframework.jms.support.destination provides various strategies for managing JMS destinations, such as providing a service locator for destinations stored in JNDI.

Finally, the package org.springframework.jms.connection provides an implementation of the ConnectionFactory suitable for use in standalone applications. It also contains an implementation of Spring's PlatformTransactionManager for JMS (the cunningly named JmsTransactionManager). This allows for seamless integration of JMS as a transactional resource into Spring's transaction management mechanisms.