SUN Sun Certified Web Component Developer for J2EE 5 Sample Questions:

1. 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. You need to create an event listener that constructs the preferences factory and stores it in the application scope for later use. Furthermore, this factory requires that the URL to a database must be declared in the deployment descriptor like this:
4 2. <context-param>
4 3. <param-name>prefsDbURL</param-name>
4 4. <param-value>
4 5. jdbc:pointbase:server://dbhost:4747/prefsDB
4 6. </param-value>
4 7. </context-param>
Which partial listener class will accomplish this goal?

A) public class PrefsFactoryInitializer implements ServletContextListener { public void contextInitialized(ServletContextEvent e) {
ServletContext ctx = e.getServletContext();
String prefsURL = ctx.getInitParameter("prefsDbURL");
PreferencesFactory myFactory = makeFactory(prefsURL);
ctx.setAttribute("myPrefsFactory", myFactory);
}
// more code here
}
B) public class PrefsFactoryInitializer implements ServletContextListener { public void contextCreated(ServletContext ctx) {
String prefsURL = ctx.getInitParameter("prefsDbURL");
PreferencesFactory myFactory = makeFactory(prefsURL);
ctx.setAttribute("myPrefsFactory", myFactory);
}
// more code here
}
C) public class PrefsFactoryInitializer implements ContextListener {
public void contextInitialized(ServletContextEvent e) {
ServletContext ctx = e.getContext();
String prefsURL = ctx.getParameter("prefsDbURL");
PreferencesFactory myFactory = makeFactory(prefsURL);
ctx.putAttribute("myPrefsFactory", myFactory);
}
// more code here
}
D) public class PrefsFactoryInitializer implements ContextListener {
public void contextCreated(ServletContext ctx) {
String prefsURL = ctx.getParameter("prefsDbURL");
PreferencesFactory myFactory = makeFactory(prefsURL);
ctx.putAttribute("myPrefsFactory", myFactory);
}
// more code here
}

2. Which two about WAR files are true? (Choose two.)

A) WAR files must be created by using archive tools designed specifically for that purpose.
B) WAR files must be located in the web application library directory.
C) The web container must serve the content of any META-INF directory located in a WAR file.
D) WAR files must contain the web application deployment descriptor.
E) The web container must allow access to resources in JARs in the web application library directory.

3. A JSP page needs to set the property of a given JavaBean to a value that is calculated with the JSP page. Which three jsp:setProperty attributes must be used to perform this initialization? (Choose three.)

A) value
B) attribute
C) id
D) val
E) name
F) property
G) param

4. One of the use cases in your web application uses many session-scoped attributes. At the end of the use case, you want to clear out this set of attributes from the session object.
Assume that this static variable holds this set of attribute names:
2 01. private static final Set<String> USE_CASE_ATTRS;
2 02. static {
2 03. USE_CASE_ATTRS.add("customerOID");
2 04. USE_CASE_ATTRS.add("custMgrBean");
2 05. USE_CASE_ATTRS.add("orderOID");
2 06. USE_CASE_ATTRS.add("orderMgrBean");
207. }
Which code snippet deletes these attributes from the session object?

A) for ( String attr : USE_CASE_ATTRS ) {
session.remove(attr);
}
B) for ( String attr : USE_CASE_ATTRS ) {
session.removeAttribute(attr);
}
C) session.deleteAllAttributes(USE_CASE_ATTRS);
D) for ( String attr : USE_CASE_ATTRS ) {
session.deleteAttribute(attr);
}
E) session.removeAll(USE_CASE_ATTRS);

5. Which statement is true about web container session management?

A) To activate URL rewriting, the developer must use the
HttpServletResponse.setURLRewriting method.
B) Access to session-scoped attributes is guaranteed to be thread-safe by the web container.
C) The JSESSIONID cookie is stored permanently on the client so that a user may return to the web application and the web container will rejoin that session.
D) If the web application uses HTTPS, then the web container may use the data on the
HTTPS request stream to identify the client.

Solutions: