Given an HttpServletRequest request and an HttpServletResponse response：
41.HttpSession session = null；
42.// insert code here
43.if（session == null） {
44.// do something if session does not exist
45.} else {
46.// do something if session exists47. }
To implement the design intent，which statement must be inserted at line 42？（）

多项选择题WhichtwostatementsaretrueaboutusingtheisUserInRolemethodtoimplementsecurityinaJavaEEapplication？（）

A.It can be invoked only from the doGet or doPost methods.
B.It can be used independently of the getRemoteUser method.
C.Can return "true" even when its argument is NOT defined as a valid role name in the deployment descriptor.
D.Using the isUserInRole method overrides any declarative authentication related to the method in which it is invoked.

多项选择题Whichtwoarerequiredelementsfortheelementofawebapplicationdeploymentdescriptor？（）

A.<realm-name>
B.<url-pattern>
C.<description>
D.<web-resource-name>
E.<transport-guarantee>

单项选择题Whichelementofawebapplicationdeploymentdescriptorelementisrequired？（）

A.<realm-name>
B.<auth-method>
C.<security-role>
D.<transport-guarantee>
E.<web-resource-collection>

多项选择题Whichtwostatementsaretrueaboutthesecurity-relatedtagsinavalidJavaEEdeploymentdescriptor？（）

A.Every  tag must have at least one  tag.
B.A  tag can have many  tags.
C.A given  tag can apply to only one  tag.
D.A given  tag can contain from zero to many  tags.
E.It is possible to construct a valid  tag such that，for a given resource，no user rolescan access that resource.

单项选择题You web application uses a lot of Java enumerated types in the domain model of the application. Built intoeach enum type is a method， getDisplay（）， which returns a localized， user-oriented string. There are manyuses for presenting enums within the web application， so your manager has asked you to create a customtag that iterates over the set of enum values and processes the body of the tag once for each value； settingthe value into a page- scoped attribute called， enumValue. Here is an example of how this tag is used： 10. 11. 12.${enumValue.display} 13. 14. You have decided to use the Simple tag model to create this tag handler. Which tag handler method willaccomplish this goal？（）

A.
B.
C.
D.