Your web site has many user-customizable features， for example font and color preferences on web pages.Your IT department has already built a subsystem for user preferences using the Java SE platform’s lang.util.prefs package APIs， and you have been ordered to reuse this subsystem in your web application. Youneed to create an event listener that constructs the preferences factory and stores it in the applicationscope for later use. Furthermore， this factory requires that the URL to a database must be declared in thedeployment descriptor like this：

Servlet A receives a request that it forwards to servlet B within another web application in the same webcontainer. Servlet A needs to share data with servlet B and that data must not be visible to other servlets inA’s web application.
In which object can the data that A shares with B be stored？（）

The sl：shoppingList and sl：item tags output a shopping list to the response and are used as follows：
11.<sl：shoppingList>
12.<sl：item name="Bread" />
13.<sl：item name="Milk" />
14.<sl：item name="Eggs" />
15.</sl：shoppingList>
The tag handler for sl：shoppingList is ShoppingListTag and the tag handler for sl：item is ItemSimpleTag.ShoppingListTag extends BodyTagSupport and ItemSimpleTag extends SimpleTagSupport.Which is true？（）

Given the JSP code：
<% request.setAttribute（"foo"， "bar"）； %>and the Classic tag handler code：
5. public int doStartTag（） throws JspException {
6. // insert code here
7. // return int
8. }
Assume there are no other "foo" attributes in the web application.
Which invocation on the pageContextobject，inserted at line 6，assigns "bar" to the variable x？（）

You are building a web application that will be used throughout the European Union； therefore， it has significant internationalization requirements. You have been tasked to create a custom tag that generates amessage using the java.text.MessageFormat class. The tag will take the resourceKey attribute and a variable number of argument attributes with the format， arg. Here is an example use of this tag and itsoutput：  generates： The disk "MyDisk"contains 1247 file（s）.
Which Simple tag class definition accomplishes this goal of handling a variable number of tag attributes？（）