Most of the communications between components that you have seen so far are synchronous: one class calls another, a managed bean invokes an EJB, which calls an entity, and so on. 

   Message-oriented middleware (MOM) is software (a provider) that enables asynchronous 

messages between heterogeneous systems. It can be seen as a buffer between systems that 

produce and consume messages at their own pace

    JMS is a standard Java API that allows applications to create, send, receive, and read messages 

asynchronously

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就跟我们在计算机系统中常提到的生产者与消费者一样.消费者,生产者不需要互相知道对方的存在.as long as the sender and receiver agree on the message format and the intermediate 

destination

consumer

provider

基于JMS 和MOM 的信息交换系统研究

JMS