Oracle Oracle Certifications 1Z0-858 Questions & Answers

• Question 251:

  The sl:shoppingList and sl:item tags output a shopping list to the response and are used as follows:

  11.

  12.

  13.

  14.

  15.

  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?

  A. ItemSimpleTag can find the enclosing instance of ShoppingListTag by calling getParent() and casting the result to ShoppingListTag.

  B. ShoppingListTag can find the child instances of ItemSimpleTag by calling super.getChildren() and casting each to an ItemSimpleTag.

  C. It is impossible for ItemSimpleTag and ShoppingListTag to find each other in a tag hierarchy because one is a Simple tag and the other is a Classic tag.

  D. ShoppingListTag can find the child instances of ItemSimpleTag by calling getChildren() on the PageContext and casting each to an ItemSimpleTag.

  E. ItemSimpleTag can find the enclosing instance of ShoppingListTag by calling findAncestorWithClass() on the PageContext and casting the result to ShoppingListTag.

  Correct Answer: A

• Question 252:

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

  A. HttpSession

  B. ServletConfig

  C. ServletContext

  D. HttpServletRequest

  E. HttpServletResponse

  Correct Answer: D

• Question 253:

  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:

  42.

  43.

  prefsDbURL

  44.

  45.

  jdbc:pointbase:server://dbhost:4747/prefsDB

  46.

  47.

  Which partial listener class will accomplish this goal?

  A. 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}

  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 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}

  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}

  Correct Answer: C

• Question 254:

  A developer wants a web application to be notified when the application is about to be shut down. Which two actions are necessary to accomplish this goal? (Choose two.)

  A. include a listener directive in a JSP page

  B. configure a listener in the TLD file using the element

  C. include a element in the web application deployment descriptor

  D. configure a listener in the application deployment descriptor, using the element

  E. include a class implementing ServletContextListener as part of the web application deployment

  F. include a class implementing ContextDestroyedListener as part of the web application deployment

  G. include a class implementing HttpSessionAttributeListener as part of the web application deployment

  Correct Answer: DE

• Question 255:

  You want to create a filter for your web application and your filter will implement javax.servlet.Filter.

  Which two statements are true? (Choose two.)

  A. Your filter class must implement an init method and a destroy method.

  B. Your filter class must also implement javax.servlet.FilterChain.

  C. When your filter chains to the next filter, it should pass the same arguments it received in its doFilter method.

  D. The method that your filter invokes on the object it received that implements javax.servlet.FilterChain can invoke either another filter or a servlet.

  E. Your filter class must implement a doFilter method that takes, among other things, an HTTPServletRequest object and an HTTPServletResponse object.

  Correct Answer: AD

• Question 256:

  Which three are true about the HttpServletRequestWrapper class? (Choose three.)

  A. The HttpServletRequestWrapper is an example of the Decorator pattern.

  B. The HttpServletRequestWrapper can be used to extend the functionality of a servlet request.

  C. A subclass of HttpServletRequestWrapper CANNOT modify the behavior of the getReader method.

  D. An HttpServletRequestWrapper may be used only by a class implementing the javax.servlet.Filter interface.

  E. An HttpServletRequestWrapper CANNOT be used on the request passed to the RequestDispatcher.include method.

  F. An HttpServletRequestWrapper may modify the header of a request within an object implementing the javax.servlet.Filter interface.

  Correct Answer: ABF

• Question 257:

  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 pageContext object, inserted at line 6, assigns "bar" to the variable x?

  A. String x = (String) pageContext.getAttribute("foo");

  B. String x = (String) pageContext.getRequestScope("foo");

  C. It is NOT possible to access the pageContext object from within doStartTag.

  D. String x = (String)pageContext.getRequest().getAttribute("foo");

  E. String x = (String) pageContext.getAttribute("foo",PageContext.ANY_SCOPE);

  Correct Answer: D

• Question 258:

  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 a message 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 its output:

  generates:

  The disk "MyDisk" contains 1247 file(s).

  Which Simple tag class definition accomplishes this goal of handling a variable number of tag attributes?

  A. public class MessageTag extends SimpleTagSupportimplements VariableAttributes {private Map attributes = new HashMap();public void setVariableAttribute(String uri,String name, Object value) {this.attributes.put(name, value);}// more tag handler methods}

  B. The Simple tag model does NOT support a variable number of attributes.

  C. public class MessageTag extends SimpleTagSupportimplements DynamicAttributes {private Map attributes = new HashMap();public void putAttribute(String name, Object value) {this.attributes.put (name, value);}// more tag handler methods}

  D. public class MessageTag extends SimpleTagSupportimplements VariableAttributes {private Map attributes = new HashMap();public void putAttribute(String name, Object value) {this.attributes.put (name, value);}// more tag handler methods}

  E. public class MessageTag extends SimpleTagSupportimplements DynamicAttributes {private Map attributes = new HashMap();public void setDynamicAttribute(String uri, String name,Object value) {this.attributes.put(name, value);}// more tag handler methods}

  Correct Answer: E

• Question 259:

  Which implicit object is used in a JSP page to retrieve values associated with entries in the deployment descriptor?

  A. config

  B. request

  C. session

  D. application

  Correct Answer: D

• Question 260:

  You have created a JSP that includes instance variables and a great deal of scriptlet code. Unfortunately, after extensive load testing, you have discovered several race conditions in your JSP scriptlet code. To fix these problems would require significant recoding, but you are already behind schedule. Which JSP code snippet can you use to resolve these concurrency problems?

  A. <%@ page isThreadSafe='false' %>

  B. <%@ implements SingleThreadModel %>

  C. <%! implements SingleThreadModel %>

  D. <%@ page useSingleThreadModel='true' %>

  E. <%@ page implements='SingleThreadModel' %>

  Correct Answer: A