A. session.unbind（“key”）；
B. session.remove（“key”）；
C. session.removeAttribute（“key”）；
D. session.unbindAttribute（“key”）；
E. session.deleteAttribute（“key”）；

A. Access to session-scoped attributes is guaranteed to be thread-safe by the web container.
B. To activate URL rewriting， the developer must use the HttpServletResponse.setURLRewriting method.
C. If the web application uses HTTPS， then the web container may use the data on the HTTPS request stream to identify the client.
D. The JSESSIONID cookie is stored permanently on the client so that a user may return to the web application and the web container will rejoin that session.

A. Tag files can only be accessed using a tagdir attribute.
B. The sort.jsp page translates successfully and invokes the tag defined by beta.tag.
C. The sort.jsp page produces a translation error because a taglib directive must always have a uri attribute.
D. Tag files can only be placed in /WEB-INF/tags， and NOT in any subdirectories of /WEB-INF/tags.
E. The tagdir attribute in line 2 can be replaced by a uri attribute if a TLD referring to beta.tag is created and added to the web application.

A. It may iterate over arrays， collections， maps and strings.
B. The body of the tag may contain EL code， but not scripting code.
C. When looping over collections， a loop status object may be used in the tag body.
D. It may iterate over a map， but only the key of the mapping may be used in the tag body.
E. When looping over integers （for example begin1=’1’ end=’10’）， a loop status object may not be used in the tag body.

A. The prefix ‘java’ is reserved.
B. The URI ‘myTags’ must be properly mapped to a TLD file by the web container.
C. A translation error occurs because the prefix is considered identical by the web container.
D. For the tag usage ， the tag1 must be unique in the union of tag names in ‘myTags’  and ‘moreTags

A. session = response.getSession（）；
B. session = request.getSession（）；
C. session = request.getSession（true）；
D. session = request.getSession（false）；
E. session = request.getSession（“jsessionid”）；

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>

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

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

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