The Java Message Service (JMS) API is a Java Message Oriented Middleware (MOM) API for sending messages between two or more clients. JMS is a part of the Java Platform, Enterprise Edition, and is defined by a specification developed under the Java Community Process as JSR 914.
Reference:
http://en.wikipedia.org/wiki/Java_Message_Service
Reference:
http://en.wikipedia.org/wiki/Java_Message_Service