Java Messaging Service- ( JMS )

The Java Message Service was developed by Sun Microsystems to provide a means for Java programs to access enterprise messaging systems. Enterprise messaging systems, often known as message oriented middleware (MOM), provide a mechanism for integrating applications in a loosely coupled, flexible manner. They provide asynchronous delivery of data between applications on a store and forward basis; that is, the applications do not communicate directly with each other, but instead communicate with the MOM, which acts as an intermediary.

JMS is a set of interfaces and associated semantics that define how a JMS client accesses the facilities of an enterprise messaging product.

Prior to JMS, each MOM vendor provided application access to their product through a proprietary API, often available in multiple languages, including the Java language. JMS provides a standard, portable way for Java programs to send and receive messages through a MOM product. Programs written with JMS will be able to run on any MOM that implements the JMS standard. The key to JMS portability is the fact that the JMS API is provided by Sun as a set of interfaces. Products that want to provide JMS functionality do so by supplying a provider that implements these interfaces. As a developer, you build a JMS application by defining a set of messages and a set of client applications that exchange those messages.

The objectives of JMS, as stated in the specification, are to:
* Define a common set of messaging concepts and facilities.
* Minimize the concepts a programmer must learn to use enterprise messaging.
* Maximize the portability of messaging applications.
* Minimize the work needed to implement a provider.
* Provide client interfaces for both point-to-point and pub/sub domains. "Domains" is the JMS term for the messaging models discussed earlier. (Note: A provider need not implement both domains.)