A. ${cart = null} B. C.

Given that a scoped attribute cart exists only in a user’s session， which two， taken independently， ensure the scoped attribute cart no longer exists？（）

A. ${cart = null} 
B. <c：remove var="cart" /> 
C. <c：remove var="${cart}" /> 
D. <c：remove var="cart" scope="session" /> 
E. <c：remove scope="session">cart</c：remove> 
F. <c：remove var="${cart}" scope="session" /> 
G. <c：remove scope="session">${cart}</c：remove>

单项选择题Which option prevents the exception thrown by my：errorProne from invoking the error page mechanism and outputs the message  File not found  in the response？（）

A.A
B.B
C.C
D.D
E.E

单项选择题Whichinterfacemustaclassimplementsothatinstancesoftheclassarenotifiedafteranyobjectisaddedtoasession？（）

A. javax.servlet.http.HttpSessionListener
B. javax.servlet.http.HttpSessionValueListener
C. javax.servlet.http.HttpSessionBindingListener
D. javax.servlet.http.HttpSessionAttributeListener

单项选择题The tl：task tag supplies information about a single task while the tl：taskList tag does the final output. The tag handler for tl：taskList is TaskListTag. The tag handler for tl：task is TaskTag. Both tag handlers extend BodyTagSupport.  Which allows the tl：taskList tag to get the task names from its nested tl：task children？（）

A.A
B.B
C.C
D.D
E.E

多项选择题Whichthreearevalidvaluesforthebody-contentattributeofatagdirectiveinatagfile？（）

A. EL
B. JSP
C. empty
D. dynamic
E. scriptless
F. tagdependent

单项选择题A developer is designing a web application that must support multiple interfaces， including：   • an XML web service for B2B • HTML for web-based clients • WML for wireless customers   Which design pattern provides a solution for this problem？()

A. Session Façade
B. Business Delegate
C. Data Access Object
D. Model-View-Controller
E. Chain of Responsibility