必须从名为"bookEJBObject"的EJBObject中检索先前保存的句柄。我们编写了以下远程接口，以重新启动对该特定请求的处理：
1. ObjectInputStream stream =
2. newObjectInputStream(new FileInputStream(fileName));
3.
4. Handle bookHandle = (Handle) stream.readObject();
5.
6. BookRemoteInterfacebookEjbObject = (BookRemoteInterface) XX() ; 第6行的方法XX()应替换以下哪项？
javax.rmi.PortableRemoteObject(bookHandle.getEJBObject(), BookRemoteInterface);
javax.rmi.PortableRemoteObject(EJBObject, BookRemoteInterface);
javax.rmi.PortableRemoteObject.narrow(bookHandle.getEJBObject(), BookRemoteInterface.class);
javax.rmi.PortableRemoteObject.narrow(bookHandle, BookRemoteInterface);
BookHandle.getEJBObject()
