EJB客户端从来不直接处理bean实例，他们通常是从容器通过EJBOBject处理。容器对于实例池是开放的，然后在需要的时候重用bean class的实例并对客户端隐藏实现的具体细节。-EJB client never directly deal with bean instance, they are usually from the container through EJBOBject treatment. Container for instance pool is open, and