Enterprise JavaBeans

Enterprise JavaBeans

JMS and Message-Driven Bean

What is JMS?

JMS is a API for accessing messaging systems. It's analogous to JDBC (Java Database Connectivity): where JDBC is an API that you can use to access many different relational databases, JMS provides the same vendor-independent access to messaging services. Many vendors currently support JMS including IBM's MQSeries, BEA's Weblogic JMS service, and Progress' SonicMQ to name a few.

JMS lets you send messages from one JMS client to another through a messaging service, sometimes called a message broker or router. A message is a type object in JMS, which has two parts: a header and a message body. The header is composed of routing information and metadata about the message. The message body carries the application data or payload.

Message Types:

simple text (TextMessage)

serializable objects (ObjectMessage)

a collection of properties (MapMessage), byte streams (BytesMessage)

primitive values streams (StreamMessage)

no payload (Message).