Given a Filter class definition with this method：
21.public void doFilter（ServletRequest request，
22.ServletResponse response，
23.FilterChain chain）
24.throws ServletException， IOException {
25.// insert code here26. }
Which should you insert at line 25 to properly invoke the next filter in the chain，or the target servlet if thereare no more filters？（）

单项选择题Click the Exhibit button.  Given the web application deployment descriptor elements： 11. 12.ParamAdder 13.com.example.ParamAdder 14.... 31. 32.ParamAdder 33.Destination 34.... 55. 56.Destination 57. dest Destination 58. What is the result of a client request of the Source servlet with no query string？（）

A.The output "filterAdded = null" is written to the response stream.
B.The output "filterAdded = addedByFilter" is written to the response stream.
C.An exception is thrown at runtime within the service method of the Source servlet.
D.An exception is thrown at runtime within the service method of the Destination servlet.

多项选择题Given： String value = getServletContext（）.getInitParameter（ foo ）； in an HttpServlet and a web applicationdeployment descriptor that contains： <context-param> <param-name>foo< param-name> <param-value>frodo< param-value> < context-param> Which two are true？（）

A.The foo initialization parameter CANNOT be set programmatically.
B.Compilation fails because getInitParameter returns type Object.
C.The foo initialization parameter is NOT a servlet initialization parameter.
D.Compilation fails because ServletContext does NOT have a getInitParameter method.
E.The foo parameter must be defined within the  element of the deployment descriptor.

多项选择题Forwhichthreeeventscanwebapplicationeventlistenersberegistered？（）

A.When a session is created
B.After a servlet is destroyed
C.When a session has timed out
D.When a cookie has been created
E.When a servlet has forwarded a request
F.When a session attribute value is changed

多项选择题Your web application uses a simple architecture in which servlets handle requests and then forward to aJSP using a request dispatcher. You need to pass information calculated in the servlet to the JSP for view generation.This information must NOT be accessible to any other servlet，JSP or session in the webapp. Which two techniques can you use to accomplish this goal？（）

A.Add attributes to the session object.
B.Add attributes on the request object.
C.Add parameters to the request object.
D.Use the pageContext object to add request attributes.
E.Add parameters to the JSP’s URL when generating the request dispatcher.

多项选择题A developer chooses to avoid using SingleThreadModel but wants to ensure that data is updated in athread-safe manner. Which two can support this design goal？（）

A.Store the data in a local variable.
B.Store the data in an instance variable.
C.Store the data in the HttpSession object.
D.Store the data in the ServletContext object.
E.Store the data in the ServletRequest object.