Bean的区别

What is the difference between Message Driven Beans and Stateless Session beans?
消息驱动的Bean和无状态的会话Bean有什么区别？

In several ways, the dynamic creation and allocation of message-driven bean instances mimics the behavior of stateless session EJB instances, which exist only for the duration of a particular method call.
在一些情况下，动态的创建，分配消息驱动的Bean的实例与无状态的会话Bean很类似，它只存在于特定的方法调用期间。

However, message-driven beans are different from stateless session EJBs (and other types of EJBs) in several significant ways:
但是，消息驱动的Bean与无状态的会话Bean(包括其它类型的EJB)有一些显著的不同：

Message-driven beans process multiple JMS messages asynchronously, rather than processing a serialized sequence of method calls.
消息驱动的Bean处理多个JMS消息是异步的，而不是方法调用的顺序的。

Message-driven beans have no home or remote interface, and therefore cannot be directly accessed by internal or external clients.
消息驱动的Bean没有home和远程接口，所以不能在内部或者外部的客户端直接使用。

Clients interact with message-driven beans only indirectly, by sending a message to a JMS Queue or Topic.
客户端与消息驱动的Bean交互，只能非直接的，通过发送一个消息给JMS队列或者主题。

Only the container directly interacts with a message-driven bean by creating bean instances and passing JMS messages to those instances as necessary.
只有容器可以直接与消息驱动的Bean交互，创建bean的实力，传递JMS消息给那些需要的实例。

The Container maintains the entire lifecycle of a message-driven bean; instances cannot be created or removed as a result of client requests or other API calls.
容器管理者消息驱动的Bean的整个生命周期，实例不能被客户的请求或者其它API的调用而创建或者移除。