多项选择题
For which three events can web application event listeners be registered？ （）
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 AdeveloperchoosestoavoidusingSingleThreadModelbutwantstoensurethatdataisupdatedinathread-safemanner.Whichtwocansupportthisdesigngoal？（）
多项选择题 ARequestDispatchercanbeobtainedfromwhichtwoobjects？（）
多项选择题 Inwhichtwolocationscanlibrarydependenciesbedefinedforawebapplication？（）
