单项选择题 Whichdefinesthewelcomefilesinawebapplicationdeploymentdescriptor？（）

单项选择题 Given this fragment from a Java EE deployment descriptor： 341.<error-page> 342.<exception-type>java.lang.Throwable</exception-type>  343.<location>/mainError.jsp</location> 344.</error-page> 345.<error-page> 346.<exception-type>java.lang.ClassCastException</exception-type>  347.<location>/castError.jsp</location> 348.</error-page> If the web application associated with the fragment above throws a ClassCastException.Which statement is true？（）

单项选择题 You have created a servlet that generates weather maps. The data for these maps is calculated by aremote host. The IP address of this host is usually stable， but occasionally does have to change as thecorporate network grows and changes. This IP address used to be hard coded， but after the fifth change tothe IP address in two years， you have decided that this value should be declared in the deploymentdescriptor so you do NOT have the recompile the web application every time the IP address changes. Which deployment descriptor snippet accomplishes this goal？（）