Pass4side SUN 310-052考试题库分享（16-20）

16. Your web application requires access to several different services, so you created a Service Locator class to be
used by the UI developers on the team. New services with different interfaces are occasionally added.
Unfortunately, the caching benefits of the Service Locator class are NOT being realized because a new instance of
this class is being created in every backing bean method that requires a service. Which pattern should you apply to
eliminate this problem?
A. Bridge
B. Singleton
C. Prototype
D. Factory Method
E. Business Delegate
Answer: B

17. What are two benefits of using the Value List Handler pattern? (Choose two.)
A. improves network performance
B. facilitates exposing existing services
C. provides an alternative to potentially inefficient EJB finders
D. facilitates post-processing across heterogeneous requests
E. provides a mechanism to support shared elements of composite views
Answer: AC

18. What are two capabilities of the Abstract Factory pattern? (Choose two.)
A. creates whole-part hierarchies
B. creates families of related objects
C. enforces dependencies between concrete classes
D. specifies the types of objects to create using a sample instance
E. separates the construction of a complex object from its representation
Answer: BC

19. A teenage fashion web site, includes a set of pages for displaying and browsing their catalog, as well as pages
for making fashion suggestions that also display tables of catalog entries. Currently, the JSP code uses scriptlets
that perform database SELECT statements and format the results in HTML tables. You have been hired to help
reduce the maintenance overhead when either the look is modified or the database schema changes. Which two
patterns, used together, do you apply to reduce this maintenance overhead? (Choose two.)
A. View Helper
B. Front Controller
C. Composite View
D. Data Access Object
Answer: AD

20. A new security feature has been requested for an existing web application with the following requirements:
All requests must be logged to a secure database.
Each request must be time-stamped with the start and completion times.
Each request must contain the IP address of the client that made the request.
Which pattern is most applicable for this new feature?
A. Strategy
B. Front Controller
C. Abstract Factory
D. Intercepting Filter
E. Model View Controller
Answer: D

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