Saturday, February 28, 2009

SCEA 5.0 Exam Questions - 4

Few more questions for the exam:

41. Which design pattern is usefull for hiding the construction and implementation details of an object?

A. Flyweight
B. Singleton
C. Abstract Factory
D. Chain of Command
Correct Answer: C

42. Some media players use a virtual proxy for image loading. What is the benefit of using a virtual proxy?

A. It controls access to the original object.
B. It defers creation of expensive objects until necessary.
C. It provides a local representation for an object in a different address space.
D. It is a replacement for a bare pointer that performs additional actions when an object is accessed.

Correct Answer: B

43. What are two capabilities of the Decorator pattern ? (Choose two.)

A. Provides a unified interafe to a subsystem
B. Converts the interface of a class into another interface
C. Is used when the base class is unavailable for subclassing
D. Promotes loose coupling by keeping objects from referring to each other
E. Modifies responsibilities to individual objects dynamically and transparently

Correct Answers: C, E

44. You are building a web application that must integrate to a content management system(CMS). Your company currently has a homegrown CMS, but management is considering purchasing a new CMS.
Unfortunately, you have little confidence that their lates choice, BigCMS, is likely to be the final decision. After analyzing the interface to BigCMS, you find that its interface is different from the homegrown CMS. Furthermore, you suspect that any other third-party CMS will have yet another interface.

What is the simplest pattern that would isolate your web application from the interface of the CMS tool ?
A. Proxy
B. Bridge
C. Adapter
D. Service Locator
E. Business Delegate

Correct Answer: C

45. What is a benefit of using the Transfer Object pattern ?

A. Reduces requests across the network
B. Avoids the overhead of using EJB finder methods for large searches
C. Separates the business state and related behavior from the rest of the appliation
D. Implements parent-child relationships efficiently when imlementing Business Objects

Correct Answer: A

46. What are two benefits of using the Value List Handler pattern? (Choose two.)

A. Improves network performence
B. Facilitates exposing existing services
C. Provides an alternative to petentially inefficient EJB finders.
D. Facilitates post-processing across heterogeneous requsts
E. Provides a mechanism to support shared eleemnts of composite views

Correct Answers: A, C

47. A company created its own MVC-like framework in the years before struts and JSF. Unfortunately, the company's Front Controller has become bloated with too many features including fine-grained authorization, view dispatching, and business logic invocation. Which three patterns could be applied to reduce the complexity of the Front Controller? (choose three.)

A. Mediator
B. Command
C. View Helper
D. Intercepting Filter
E. Composite View.
F. Application controller

Correct Answers: B, D, F

48. What are two advantages of the Business Delegate pattern? (Choose two.)

A. Increases the scalability of remote services
B. Decouples presentation logc from business logic
C. Avoids unnecessary invocation of remote services
D. Hides underlying communication details of the service
E. Enables transparent presistent storage of the business entity

Correct Answers: C, D

49. What are two advantages of a thin client, three tier architecture over a thick client, two-tier architecture ? (choose two.)

A. It is more secure.
B. It is more reliable
C. It is easier to maintain.
D. It makes it easier to manage the application deployment.

Correct Answers: C, D

50. A teenage fashion website, has a multi-tier web application with 103 web servers, 12 middle-tier servers, and a large RDBMS server with more than enough capacity to support peak loads. You are the architect of the system, and you are concerned about reliability of the web application. Which change could you make to improve reliability ?

A. Add additional web servers.
B. Add additional database servers
C. Add additional middle-tier servers
D. Reduce the number of web servers
E. Reduce the number of middle-tier servers.

Correct Answer: B

51. Which is NOT a valid reason to separate presentation from business logic ?

A. Improved scalability
B. Improved performence
C. Separation of cencerns
D. Improved maintainability

Correct Answer: B

52. A company is considering re-architecting their application from a two-tier to a three-tier architecture. To see what impact the new architecture would have on their non-funtional requirements (NFRs), they created a prototype.
When they tested the prototype based on their three-tier architecture they noticed, contrary to expectations, that the prototype was less scalable than the original two-tier solution.
Which two statements explain the result? (Choose two.)

A. Clients end up competing for CPU cycles on the common business logic tier.
B. Clients end up competing for resources on the back-end database used by the application.
C. Clients did NOT share interest in any domain objects, but the business tier spent too much time coordinating among clients anyway.
D. Clients did NOT share interest in any domain objects and the business tier ran out of memory to represent all domain objects required by the clients.

Correct Answers: A, D

53. Which two statements are true only when implementing rich client applications, and NOT when implementing web browser-based clients that support only HTML? (Choose two.)
A. Information can be sent to the client by the server, without client polling
B. Information can be encrypted prior to delivering it to the client and decrypted when received to the client.
C Information can be compressed prior to delivering it to the client and decompressed when received ro the client.
D. Information can be delivered to the client incrementally, without requiring that the server deliver all the information to be presented to the client on each update.

Correct Answers: A, D

54. A bank designed its first-generation web-based banking system aroung a Java technology rich client application that interacts with server-side service objects implemented as stateful session beans in a portable Java EE application. For their second-generation system, the company wants to open the architecture to other types of clients. The company is considering exposing its existing stateful session bean service as a web service. Which statement is true ?

A. Session beans cannot be exposed as web services.
B Stateful session beans cannot be exposed as web services.
C. Stateful session beans are automatically exposed as web services.
D. Stateful session beans annotated with @WebService are exposed as web services.

Correct Answer: B

55. Brokers at a firm currently use a two-tier application to execute stock transactions on behalf the their customers. Business componens within the application enforce a number of complex business rules that ensure that stock transactions are executed properly.
Management has decided that clients should be able to execute their own transactions to streamline operations. Management also wants clients to run the same existing two-tier applications from their home computers. They have hired you to advise them on how to proceed to unsure that no illegal stock transactions are executed once the application is available directly to clients.

Which two recommendations should you give to this brokerage firm? (Choose two.)
A. The code already checks for correct execution so they can deliver the application to clients "as is"
B. Checks for correctness should be rewritten as database constraints because the application running on the client might be modified.
C. The application should be re-architected as a thee-tier solution. That way, validation checks can be moved to a server-side business tier, which remains trustworthy.
D. The application should be obfuscated before it is delivered to the client. That way, clients cannot modify it. Therefore, the validation checks currently implemented will remain trustworthy.

Correct Answers: B, C

56. A travel company re-architected its application from a two-tier to a three-tier architecture. To see what impact the new architecture would have on its non-functional requirements(NFR), the company intends to build a prototype based on the new architecture. The company compared the MFR metrics associated with the new prototype against the metrics from their original two-tier solution. What is an advantage of the original two-tier solution?

A. It has better availability because it has fewer single point of failure.
B. It has better manageability because each client has its own copy of the application.
C. It has better performence because each client must use is own set of domain objects.
D. It has better scalability because each client can access the database independently of other clients.

Correct Answer: A