单项选择题 You need to retrieve the username cookie from an HTTP request. If this cookie does NOT exist， then the cvariable will be null. Which code snippet must be used to retrieve this cookie object？（）

多项选择题 You are creating a servlet that generates stock market graphs. You want to provide the web browser withprecise information about the amount of data being sent in the response stream.  Which twoHttpServletResponse methods will you use to provide this information？（）

单项选择题 Your web page includes a Java SE v1.5 applet with the following declaration： 11.<object classid=’clsid：CAFEEFAC-0015-0000-0000-ABCDEFFEDCBA’ 12.width=’200’ height=’200’> 13.<param name=’code’ value=’Applet.class’ /> 14.</object> Which HTTP method is used to retrieve the applet code？（）