多项选择题
A developer chooses to avoid using SingleThreadModel but wants to ensure that data is updated in a thread-safe manner. Which two can support this design goal？（）
A. Store the data in a vocal 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.
多项选择题 ARequestDispatchercanbeobtainedfromwhichtwoobjects？（）
多项选择题 Inwhichtwolocationscanlibrarydependenciesbedefinedforawebapplication？（）
单项选择题 Which defines the welcome files in a web application deployment descriptor？（）
