Assume session is an HttpSession， and is not referenced anywhere else in ServletA. Which two changes， taken together， ensure that value is equal to “Hello” on line 23？ （）

单项选择题Given the HttpServlet code：   getServletContext（）.setAttribute（“foo”， “value”）； What is the result？（）

A. The attribute foo is placed in the application
B. A ServletContextListener registered for that servlet is notified
C. A ServletAttributeListener registered for that servlet is notified
D. An HttpSessionAttributeListener registered for that servlet is notified

单项选择题Whichisthe true choiceaboutthewebcontainerrequestprocessingmodel（）？

A. The init method on a filter is called the first time a servlet mapped to that filter is invoked
B. A filter defined for a servlet must always forward control to the next resource in the filter chain.
C. Filters associated with a named servlet are applied in the order they appear in the web application deployment descriptor file
D. If the init method on a filter throws an UnavailableException， then the container will make no further attempt to execute it