What is JMS?
Introduction to JMS
Java Messaging Service, introduced by Sun Microsystems in 1999 as part of the Java 2 Platform, Enterprise Edition (J2EE) specification, is a set of standards that describe the foundations for a message-processing middleware layer. JMS allows systems to communicate synchronously or asynchronously via both point-to-point and publish-subscribe models. Today, several vendors provide its implementations such as BEA Systems, Hewlett-Packard, IBM, Macromedia, and Oracle, thereby allowing JMS to interact with multiple vendor technologies. Java Messaging Service is one of the reliable way of communications between applications available in java.
There are two messaging models –
a) Point to Point or Queuing Model
b) Subscriber Model
a) Point to Point or Queuing Model: Here only one component is receiving the messages. The receiver and source doesn’t have knowledge about the others. The queue is responsible to hold the messages until the receiver is ready. Receiver provides acknowledgement once it receives a message.
b) Subscriber Model: The receiver has to subscribe to receive messages. Here multiple receiver can subscribe at the same time. The message is broadcasted from source to subscribers. A timing dependency is there between publisher and subscribers. The subscribers has to sense continuously to receive a message unless it has established a durable connection with publisher.