SCEA Mock Exams - 2

26    'A' has a dependency with 'B' is best expressed by:

A     Option a

B     Option b

C     Option c

D     Option d

E     Option e

F     Options b and d

G     Options d and e

Choice D is correct.

Option D shows a diagram with two packages A and B. Package A has a dependency with Package B. Hence choice D is correct.

In option A, class A extends class B. Hence choice A is incorrect.

In option B, class A implements interface B. Hence choice B is incorrect.

In option C, class A has an association relationship with interface B. Hence choice C is incorrect.

In option E, Package B has a dependency with Package A. Hence choice E is incorrect.

Since options B and E are incorrect, choices F and G are incorrect.

27    Refer to the following exhibit

From the following diagram it can be deduced that:

A     Changes to classes in the Customer package may only impact the Order package

B     Changes to classes in the Customer package will impact Order and OrderLine packages.

C     Changes to the OrderLine package will impact the Customer package

D     Changes to the Customer package will have no impact on the other two packages

Choice A is correct.

The package Order has a dependency with the package Customer. Hence any changes in the Customer Package could impact the Order Package. Hence choice A is correct.

(Fowler 109)"A dependency between two packages exists if any dependency exists between any two classes in the packages." Since Customer and OrderLine have no dependencies, choices B and C are incorrect.

Changes to the Customer package may impact the Order package. Hence choice D is incorrect.

28                Refer to the following exhibit

From the exhibit, it can be inferred that

A     1 A can have 2 Bs associated with it

B     1 A can have 4 Bs associated with it

C     1 A can have 2 to 4 Bs associated with it

D     1 A can have exactly 2 or 4 Bs associated with it

E     The multiplicity indicated is only legal in the Booch method, not in UML

Choices A, B and D are correct.

The multiplicity between A and B shown by (2,4) indicates that an A may have exactly 2 or 4 Bs associated with it. Hence choices A, B and D are correct.

Choice C is incorrect because a 2 to 4 multiplicity would be indicated as (2..4)

The multiplicity shown is perfectly legal in UML. Choice E is therefore incorrect.

29    Fragile Oars, a manufacturer of boating supplies has a mainframe based legacy application for customer and order management. Recently, Fragile Oars embarked on a project to add Internet presence to its products and services and hence created a company website. Since then, its management has realized the importance of having an eFront and wants to start conducting business over the Internet. Fragile Oars wants to use Applets as the front-end. What is the best method to connect to this legacy system?

A     Using the same applets

B     Using different applets

C     Using Java Server Pages

D     Using Java Servlets

Choice D is correct.

The best approach in this case is to have the applets talk to Servlets that can act as mediators between the applets and the Legacy system. Hence choice D is correct.

Applets and JSP are used to construct the view of an MVC application. They should not be used as controllers for dispatching requests. Hence choices B and C are incorrect.

30    Baby Bell is a new local Telephony provider in Chicago, IL. It has a legacy application for the B2B transactions with Verizon, the Incumbent Local Exchange Carrier (ILEC.) Baby Bell frequently purchases blocks of Telephone numbers from the ILEC using a CORBA RPC call. There numbers are then assigned to the customers in sequence. Sometimes customers request vanity numbers, in which case, a custom synchronous query is made on the ILEC's operational support system, to check for number's availability.

If Baby Bell were to rewrite its existing legacy code using newer J2EE technology, what technology would you choose so that both the block purchase and the individual query might be accommodated?

A     Java Applet technology for the CORBA call and custom socket programming for vanity number requests.

B     Java Servlet API for the CORBA call and JSP for the custom socket programming

C     Entity EJBs for both

D     Session EJBs for both

E     JNDI for both

F     MQ Series with a JMS based solution for both

Choice D is correct.

Session beans can be used for making both the CORBA call for block purchase of telephone numbers and the custom synchronous call to request a special vanity number. Hence choice D is correct.

Both operations represent business processes involving partner OSS. integration. Applets are not used for modeling the business workflow of a system. Hence choice A is incorrect.

JSP represent the view construction process in an MVC application. They should not be used for processing business logic. Hence choice B is incorrect.

Entity beans represent the business model of an application and provide a representation of enterprise data. They are not to be used for workflow processing which is better accomplished by using Session Beans. Hence choice C is incorrect.

JNDI provides Naming and Directory interfaces not workflow processing. Hence choice E is incorrect.

The question specifically says that a synchronous mechanism is to be used for the vanity number request. The CORBA RPC call for TN reservation is also synchronous. MQ Series is a MOM used for messaging. Messaging is an inherently asynchronous communication mechanism. Hence choice F is incorrect.

31    Julia Fractals Inc. is building a J2EE based application for Order Entry and management of their fractal software. Once the order is taken, it is submitted to a relational database. A provisioning system then queries data and makes appropriate calls to various subsystems using JMS on MQ Series. What design pattern is JMS an example of here?

A     Observer

B     Mediator

C     Adapter

D     Bridge

E     Visitor

Choice D is correct.

Bridge (GOF 151)"Decouple an abstraction from its implementation so that the two can vary independently." In this case JMS is the abstraction. The implementation could be MQ Series, TIBCO Rendezvous and Vitria Businessware. Hence choice D is correct.

Observer (GOF 293)"Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically." Hence choice A is incorrect.

Mediator (GOF 273)"Define an object that encapsulates how a set of objects interact. Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and lets you vary their interaction independently." Hence choice B is incorrect.

Adapter (GOF 139)"Convert the interface of a class into another interface clients expect. Adapter lets classes work together that couldn't otherwise because of incompatible interfaces." Hence choice C is incorrect.

Visitor (GOF 331)"Represent an operation to be performed on the elements of an object structure. Visitor lets you define a new operation without changing the classes of the elements on which it operates." Hence choice E is incorrect.

32    What design pattern best explains the use of the stub and the skeleton in CORBA based RPC applications?

A     Factory Method

B     Singleton

C     Strategy

D     Proxy

E     Decorator

Choice D is correct.

Proxy (GOF 207)"Provide a surrogate or placeholder for another object to control access to it." Hence choice E is incorrect. The applicability section (GOF 208) defines 'remote proxy' as"A remote proxy provides a local representative for an object in a different address space." Using the stub and the skeleton, CORBA based applications provide local representatives for distributed objects. Hence choice D is correct.

Factory Method (GOF 107)"Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory method lets a class defer instantiation to subclasses." Hence choice A is incorrect.

Singleton (GOF 127)"Ensure a class only has one instance, and provide a global point of access to it." Hence choice B is incorrect.

Strategy (GOF 315)"Define a family of algorithms, encapsulate each one and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it." Hence choice C is incorrect.

Decorator (GOF 175)"Attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality." Hence choice E is incorrect.

33    An application has three Stateless Session Beans - SB1, SB2 and SB3. The stubs that implement the respective Home Interfaces are SH1, SH2 and SH3. A client application performs a JNDI lookup to obtain a reference to one of these Home Objects. This is then narrowed and used to create the remote reference to the corresponding remote object. What design pattern best explains the creation of the Remote Object, in this case?

A     Prototype

B     Builder

C     Factory Method

D     Business delegate

E     Service Locator

Choice C is correct.

            Factory Method (GOF 107)"Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory method lets a class defer instantiation to subclasses."

Hence the closest pattern this concept is similar to is the Factory Method pattern. Therefore choice C is correct.

Prototype (GOF 117)" Specify the kinds of objects to create using a prototypical instance, and create new objects by copying this prototype." Hence choice A is incorrect.

Builder (GOF 97)"Separate the construction of a complex object from its representation so that the same construction process can create different representations." Hence choice B is incorrect.

            The following is taken from: http://java.sun.com/blueprints/patterns/BusinessDelegate.html

            "In distributed applications, lookup and exception handling for remote business components can be complex. When applications use business components directly, application code must change to reflect changes in business component APIs.

            These problems can be solved by introducing an intermediate class called a business delegate, which decouples business components from the code that uses them. The Business Delegate pattern manages the complexity of distributed component lookup and exception handling, and may adapt the business component interface to a simpler interface for use by views." Hence choice D is incorrect.

            The following is taken from: http://java.sun.com/blueprints/patterns/ServiceLocator.html

            "Enterprise applications require a way to look up the service objects that provide access to distributed components. Java™ 2 Platform, Enterprise Edition (J2EE) applications use Java Naming and Directory Interface (JNDI) to look up enterprise bean home interfaces, Java Message Service (JMS) components, data sources, connections, and connection factories. Repetitious lookup code makes code difficult to read and maintain. Furthermore, unnecessary JNDI initial context creation and service object lookups can cause performance problems.

            The Service Locator pattern centralizes distributed service object lookups, provides a centralized point of control, and may act as a cache that eliminates redundant lookups. It also encapsulates any vendor-specific features of the lookup process." Hence choice E is incorrect.

34    When remote calls are made on the container provided implementations of the EJBHome and EJBObject, various transactional and security checks are applied before the call is actually passed on to the bean instance.

The Container provided implementations of EJBHome and EJBObject are performing what Design Pattern's task?

A     Command

B     Adapter

C     Bridge

D     Decorator

E     Facade

Choice D is correct.

The intent of the Decorator pattern as described by GOF (175) -"Attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality." A request intended for a component is routed to the decorator instead. The decorator forwards the request to the component. It may perform pre or post processing tasks before or after forwarding the request. J2EE is filled with examples of the use of design patterns. The container provided implementations of EJBHome and EJBObject decorate bean classes by providing transactional and security functionalities.

Choice A is incorrect because Command is used to encapsulate a request as an object (GOF 233.) Choice B is incorrect because Adapter (GOF 139) converts the interface of a class into another interface clients expect. Choice C is incorrect because Bridge (GOF 151) decouples an abstraction from its implementation so that the two can vary independently and choice E is incorrect because Façade (GOF 185) provides a unified interface to a set of interfaces in a subsystem.

35    Compact Computers is a small computer assembly company. Their online application allows customers to pick and choose accessories to build their own PCs. The accessories are:

i.    Processor - 800Mhz, 1Ghz, 1.2Ghz

ii. HDD - 40 GB, 60 GB, 80 GB

iii. Memory - 128 MB, 256 MB, 512 MB

If a computer can have exactly 1 processor, 1 HDD and 1 memory stick, what pattern would be best used here?

A     Factory Method

B     Builder

C     Prototype

D     Abstract Factory

E     Singleton

Choice B is correct.

Builder (GOF 97) separates the construction of a complex object from its representation so that the same construction process can create different representations. Here the complex object is a computer. A computer is always made up of exactly one processor, one HDD and one Memory stick (problem description.) However there is no predetermined formula for combining the parts. Hence Builder is the best pattern here and B is therefore the right answer.

Answer A is incorrect because Factory Method (GOF 107) defines an interface for creating an object but lets subclasses decide which class to instantiate. You may use factories of factories to construct a complex object, but by itself, the Factory method is good for creating one out of many. Example: create one processor out of a set of three processors.

Answer C is incorrect because Prototype (GOF 117) specifies the kinds of objects to create using a prototypical instance. Example: Given a processor, if you were asked to create a computer that used multi processors, this would be a good option.

Answer D is incorrect because Abstract Factory (GOF 87) provides an interface for creating a family of related or dependent objects. If the question had defined a relation such as 'A computer of 800 MHz processor can only be coupled with a 40 GB HDD and 128 MB RAM stick', this would have been an ideal solution.

Answer E is incorrect because Singleton (GOF 127) ensures that a class has only one instance (or a well-defined number of variable instances) and appropriate global pointers are available to the instance(s).

36    Ibid is an e-auction house that auctions refurbished products. Each product has a minimum bid price. Buyers can query the system for a list of products and then select a product to bid on. They can then place a higher bid on the selected product. Transactional Integrity is very important as dirty reads, non-repeatable reads and phantom reads can lead to data inconsistency.

What technology combination might be most suitable for addressing Ibid's needs?

A     Applets for presentation and JTA/JTS for transactional integrity

B     HTML and JSP for presentation, and Servlets for data retrieval and transaction management.

C     Servlets and JSP for presentation, a stateful session bean with DAO for list retrieval and a stateless session bean for transaction management.

D     Servlets and JSP for presentation, a stateless session bean with DAO for list retrieval and CMT Entity bean for Transaction management.

E     Servlets and JSP for presentation, and a Java class to encapsulate database access and transaction management.

Choice D is correct.

The Model 2 architecture (based on the Model View Controller pattern) suggests that Servlets and JSP be used in the presentation tier. JSP combine template data with dynamic data to display dynamic content to the user. Servlets act as front controllers, and forward requests to appropriate events in the business logic tier. Unless concurrent use of shared data is involved, it may be an overkill to use Entity beans (as in the example of a simple list retrieval.) The list retrieval is therefore best accomplished by using a session bean with a Data Access Object (DAO.) Since the bidding represents concurrent use of shared data, this is best accomplished by using an Entity bean.

Choice A is incorrect because this would not be an ideal application for applets.

Choice B is incorrect because it suggests the use of Servlets for all retrieval and updates. Although possible, this is not recommended in the J2EE best practices as an ideal way when dealing with complex applications.

Choice C is incorrect because it is suggesting that a stateless session bean be used for managing concurrent access to shared data, something best done by entity beans. Choice E is incorrect because though it may be suited for smaller applications that are not very transactional in nature, the discussion specifically talks about the need for transactional integrity. Therefore this is not the recommended solution.

37    Heartbreak Hospital has two applications  - Patient Registration System and Patient Billing System. Patient Billing, an older application has CORBA interfaces for updating Billing Information. The newer Patient Registration system was built as a Java based Application. Heartbreak now wants to automatically update Billing Information from the Patient Registration Application. What Java technology may be most suited for this?

A     RMI-JRMP

B     RMI-JNI

C     RMI-IIOP

D     EJB

E     Java IDL

F     Java-CORBA Bridge

Choice E is correct.

The following is taken from:

http://java.sun.com/j2se/1.3/docs/guide/idl/

"Java IDL adds CORBA (Common Object Request Broker Architecture) capability to the Java platform, providing standards-based interoperability and connectivity. Java IDL enables distributed Web-enabled Java applications to transparently invoke operations on remote network services using the industry standard IDL (Object Management Group Interface Definition Language) and IIOP (Internet Inter-ORB Protocol) defined by the Object Management Group." Hence choice E is correct.

RMI-JRMP is used for distributed processing in a pure Java environment. Hence choice A is incorrect.

There is no indication whether the Patient Billing system supports JNI. Hence choice B is incorrect.

RMI-IIOP is useful when dealing with EJB applications. Hence choices C and D are incorrect.

There is no such thing as a Java-CORBA bridge. The Java IDL API performs that function. Hence choice F is incorrect.

38    In which of the following cases would an application not necessarily benefit from the use of Enterprise Java Beans?

A     Small Scale deployment

B     Large scale deployment

C     Transactional in nature

D     No Transactional requirements

Choices A and D are correct.

Enterprise Java Beans are best used with large and complex enterprise applications with high deployment and transactional requirements. Hence choices A And D are correct.

39    The container applies what memory management techniques in the case of Session Beans?

A     Bean Pooling

B     Bean Passivation

C     Bean Persistence

D     Bean Purge

Choices A and B are correct.

While EJBs offer business services, EJB Containers offer many peripheral services such as memory management, persistence, transactions and so on. Bean Pooling (in the case of Stateless Session Beans) and Bean Passivation (in the case of Stateful Session Beans and Entity Beans) are two techniques the container uses for managing memory. Hence choices A and B are correct.

Bean persistence refers to persisting the data represented by Entity Beans to physical storages such as Relational, Object or other databases. It has nothing to do with memory management. Therefore choice C is incorrect.

There is nothing called Bean Purge. Beans are removed when the client calls the remove() method on the Home Interface (Stateful Session Beans) and when the container decides (in the case of Stateless Session Beans and Entity Beans which reside in Bean Pools when not in use.) In the case of Entity Beans, the remove() method also deletes the data the bean instance represents. Hence choice D is incorrect.

40    Outstanding Perf is a perfume manufacturing company. The management is currently in the process of architecting a new J2EE based solution for their online catalog. If performance is paramount and session state needs to be managed as well, it would be preferable to use HTTP and HTTPSession object as opposed to using HTTPS. True/False?

A     True

B     False

Choice A is correct.

The question specifies that performance is important. There is no mention of the security requirements. Apart from providing Session State, HTTPS includes additional functionality for allowing secure communication between the client and the server. Because of all the extra processing with encryption and decryption, HTTPS is slower than HTTP. Hence in this case, it may be preferable to use HTTP (which is stateless) with HTTPSession Object (to store state on the server.) Hence choice A is correct.

41    Staledexho, A renowned catering company has just contracted your services to track their orders. An online menu is available, for each country serviced. Customers choose what they want, the quantity and provide relevant billing information. Fed Ex ships the food in a special container.

What classes and APIs are you most likely to use to support Internationalization?

A     Locale

B     Collection Interface

C     ListIterator

D     ResourceBundle

E     KeyStore

F     OutputStreamWriter

Choices A, D and F are correct.

The following is taken from:

http://developer.java.sun.com/developer/technicalArticles/Intl/IntlIntro/

"Locales are used throughout the Java class libraries to customize how data is presented and formatted. They affect language choice, collation, calendar usage, date and time formats, number and currency formats, and many other culturally sensitive data representations. If you intend to create international Java applications, you'll definitely use the java.util.Locale class. There's no getting around it; you'll use Locales to create well-behaved, internationalized, multilingual Java applications. So, if you haven't had time to explore all the JDK 1.1 international features yet, you'll get a clearer understanding of the core of the internationalization model, the Locale, as you read and understand the descriptions and examples in this article.

A Locale is a relatively simple object. It identifies a specific language and a geographic region. In fact, the only significant contents of a Locale object are language and country. Although superficially these attributes are not particularly impressive, they represent a very rich and interesting set of information. A Locale object represents the language and cultural preferences of a geographic area. Language is a fairly easy idea to grasp; cultural preferences may not be immediately clear. Dates, time, numbers, and currency are all examples of data that is formatted according to cultural expectations. Cultural preferences are tightly coupled to a geographic area; that's why country is an important element of locale. Together these two elements (language and country) provide a precise context in which information can be presented. Using Locale, you can present information in the language and form that is best understood and appreciated by the user.

Resource Bundles - This internationalization feature of the JDK provides a mechanism for separating user interface (UI) elements and other locale-sensitive data from the application logic in a program. Separating locale-sensitive elements from other code allows easy translation. It allows you to create a single code base for an application even though you may provide 30 different language versions. Although you might be predisposed to think of text only, remember that any localizable element is a resource, including buttons, icons, and menus.

The JDK uses resource bundles to isolate localizable elements from the rest of the application. The resource bundle contains either the resource itself or a reference to it. With all resources separated into a bundle, the Java application simply loads the appropriate bundle for the active locale. If the user switches locales, the application just loads a different bundle.

Resource bundle names have two parts: a base name and a locale suffix. For example, suppose you create a resource bundle named MyBundle. Imagine that you have translated MyBundle for two different locales, ja_JP and fr_FR. The original MyBundle will be your default bundle; the one used when others cannot be found, or when no other locale-specific bundles exist. However, in addition to the default bundle, you'll create two more bundles. In the example these bundles would be named MyBundle_ja_JP and MyBundle_fr_FR. The ResourceBundle.getBundle method relies on this naming convention to search for the bundle used for the active locale.

The java.util.ResourceBundle class is abstract, which means you must use a subclass of ResourceBundle. The JDK provides two subclasses: PropertyResourceBundle and ListResourceBundle. If these don't meet your needs, you can create your own subclass of ResourceBundle."

The following is taken from:

http://java.sun.com/docs/books/tutorial/i18n/text/stream.html

"The java.io package provides classes that allow you to convert between Unicode character streams and byte streams of non-Unicode text. With the InputStreamReader class, you can convert byte streams to character streams. You use the OutputStreamWriterclass to translate character streams into byte streams."

Thus we can see that Locale, ResourceBundle and OutputStreamWriter play a vital role in Java Internationalization. Hence choices A, D and F are correct.

The Collection interface, ListIterator and KeyStore are not relevant to I18N. Hence choices B, C and E are incorrect.

42    The conversion between 16-bit Unicode and 8-bit local encoding formats is done by:

A     MessageFormat and NumberFormat

B     Locale and ResourceBundle

C     Properties files

D     InputStreamReader and OutputStreamWriter

Choice D is correct.

The following is taken from:

http://java.sun.com/docs/books/tutorial/i18n/text/stream.html

"The java.io package provides classes that allow you to convert between Unicode character streams and byte streams of non-Unicode text. With the InputStreamReader class, you can convert byte streams to character streams. You use the OutputStreamWriterclass to translate character streams into byte streams." Hence choice D is correct.

MessageFormat, NumberFormat, Locale, ResourceBundle and properties files are all used in I18N. These are not however used for conversion between Unicode character format and local 8-bit byte streams. Hence choices A, B and C are incorrect.

43    Fire Hall, manufacturers of fire extinguishers, is building a corporate Intranet and wants its employees to access payroll information via the Internet. They are planning to use Applets, because of its richer GUI capabilities. The View401K applet requires a Java 1.4 plug in on the host where it is being executed. This applet will read data cached on a temporary directory in the host to calculate 401K distributions.

What are your observations on the use of Applets for this purpose?

A     The Applet technology is not a viable solution for this application because applets are subjected to the sandbox model, which prevents them from reading from or writing to the host where they are being executed.

B     The Applet technology is a viable solution for this application because the Security policy of the Java 2 Platform is totally flexible.

Choice B is correct.

The following is taken from:

http://java.sun.com/docs/books/tutorial/security1.2/overview/index.html

"JDK 1.1 introduced the concept of a "signed applet," as illustrated in the next figure. A digitally signed applet is treated like local code, with full access to resources, if the public key used to verify the signature is trusted. Unsigned applets are still run in the sandbox. Signed applets are delivered, with their respective signatures, in signed JAR (Java Archive) files.

JDK 1.2 introduces a number of improvements over JDK 1.1. First, all code, regardless of whether it is local or remote, can now be subject to a security policy. The security policy defines the set of permissions available for code from various signers or locations and can be configured by a user or a system administrator. Each permission specifies a permitted access to a particular resource, such as read and write access to a specified file or directory or connect access to a given host and port.

The runtime system organizes code into individual domains, each of which encloses a set of classes whose instances are granted the same set of permissions. A domain can be configured to be equivalent to the sandbox, so applets can still be run in a restricted environment if the user or the administrator so chooses. Applications run unrestricted, as before, by default but can optionally be subject to a security policy." As we can see, the Java 2 Security model is totally flexible. Hence choice B is correct.

44    Which of the following statements is true about SSL?

A     SSL runs above high-level application protocols such as HTTP and LDAP

B     SSL runs below TCP-IP

C    SSL runs above TCP-IP and below application protocols

D     SSL does not have anything to do with either the application or the network layer in the OSI model

Choice C is correct.

The following is taken from:

http://developer.netscape.com/docs/manuals/security/sslin/contents.htm

"The Transmission Control Protocol/Internet Protocol (TCP/IP) governs the transport and routing of data over the Internet. Other protocols, such as the HyperText Transport Protocol (HTTP), Lightweight Directory Access Protocol (LDAP), or Internet Messaging Access Protocol (IMAP), run "on top of" TCP/IP in the sense that they all use TCP/IP to support typical application tasks such as displaying web pages or running email servers.

The SSL protocol runs above TCP/IP and below higher-level protocols such as HTTP or IMAP. It uses TCP/IP on behalf of the higher-level protocols, and in the process allows an SSL-enabled server to authenticate itself to an SSL-enabled client, allows the client to authenticate itself to the server, and allows both machines to establish an encrypted connection." Therefore choice C is correct.

Choice A is incorrect because it suggests that SSL runs above application protocols.

Choice B is incorrect because it suggests that SSL runs below TCP/IP.

SSL runs between TCP/IP and HTTP. Hence choice D is incorrect.

45    What happens when the remove() method is called on the Home Interface of an Entity Bean?

A     The remote reference is invalidated

B     The bean instance is destroyed

C     The bean instance is Passivated

D     The data represented by the bean instance is deleted from the database

E     The Bean Instance moves from pooled state to ready state

Choices A and D are correct.

The remove() method, in the case of Entity Beans, invalidates the client stub, and deletes the data represented by the bean, from the database. Hence choices A and D are correct.

The bean instance is returned to the pool. It is not destroyed when the remove() method is called on an Entity Bean. Therefore choice B is incorrect.

The container passivates the bean instance whenever required (for memory management.) It is not a consequence of the remove() method though. Hence choice C is incorrect.

The Bean instance moves from the Ready State to the Pooled State upon removal, not the other way round as the point suggests. Hence choice E is incorrect.

46    What types of transactions are supported by Enterprise Java Beans?

A     Implicit Declarative Transactions

B     Explicit JTA based transactions

C     Either A or B (based on vendor implementation)

D     Both A and B

Choice D is correct.

Enterprise Java Beans specification supports both Implicit Declarative transactions and explicit Java Transaction API (JTA) based transactions. Hence choice D is correct.

47    With Entity Beans, the container automatically generates implementations of all find methods at deployment time.True/False?

A     True

B     False

The above statement is False.

The container only generates implementations of the find methods at deployment time, in the case of Container Managed Persistence.

48    What does the ejbCreate() method return in the case of Entity Beans in EJB 1.1?

A     A remote reference to the EJBObject for both BMP and CMP beans

B     The Bean's Primary Key for both BMP and CMP beans

C     A reference to itself in BMP and NULL in CMP

D     NULL value of type BeanPK in CMP and Primary Key in BMP

Choice D is correct.

In EJB1.0, the ejbCreate() method returned void. In EJB1.1, a null value of the bean's primary key type is returned by the ejbCreate() method (in CMP.) In BMP, the ejbCreate() method returns the primary key of the newly created entity. Hence choice D is correct.

The Container intercepts the return value from the Bean and returns a remote reference to the remote object, to the calling client. Hence choice A is incorrect.

Choice B suggests that the Primary Key of the newly created instance is returned in both CMP and BMP. Hence it is incorrect.

The Bean instance never returns a reference to itself upon creation. Hence choice C is incorrect.

49    You have just started a new job working for a top finance company and you have been asked to provide a user-friendly interface to an existing mainframe application. You don't have any access to the mainframes source code. What is the best technique for this?

A     It can't be done.

B     Use a screen scraper.

C     Re-write the main frame using Java and high-end Unix servers. Although it may take some time to do this in the long run this will benefit the company.

D     Write a Java front end then use CORBA to communicate with the mainframe.

E     Use the Java Native Interface (JNI) to communicate with the mainframe.

F     Use object Mapping

F     Use JMS

B is correct choice.

The key to this question is that you don't have access to the mainframes source code. A screen scraper emulates a mainframe terminal. Basically the screen scraper logs on to the mainframe like a normal user and sends requests to the mainframe and then reads the response. The problem with a screen scraper is that if you change any of the mainframes code there is always the possibility that the screen scraper will stop working.Choice A is incorrect because it can be done. Choice C would take far too long, would cost too much and is not what the customer wants. Choice D, E and F are not appropriate are would require access to the mainframes source code. Choice G is incorrect because there is no mention that the mainframe supports a messaging system. Some of them do and even provide interfaces for JMS however as it's not stated in the question then this is not the right answer.

50    The company you have been working for has released the next generation of its sales system. You have several very powerful servers and a few basic servers at your disposal. A network expert has suggested that in order to get the best possible performance out of these machine you use reverse proxy load balancing? What is reverse proxy load balancing?

A     Splitting requests evenly amongst all back end servers

B     The proxy sits behind the backend servers monitoring the performance of each one. When it notices one is being used too much it will automatically forward requests to a different server.

C     Splitting requests amongst all back end servers depending on the amount of spare CPU time each server has available.

D     A technique used to target certain requests to certain backend servers, e.g. All Servlet requests from one server. All static HTML from another.

E     A way of filtering out certain requests. It is used to protect against denial of service attacks

Choice D is correct.

Reverse proxy load balancing is generally used when you have servers with different amounts of CPUs and Memory. You might have some really powerful servers just to be used for SSL sessions and others to handle static html. Using this will maximise the performance of your applicationChoice A is a description of round-robin load distribution. Choice B doesn't describe any particular method of load balancing. Choice C is an inaccurate description of reverse-proxy load balancing and you would need access to the mainframes source code to do this. Choice E is a cross between a firewall and a standard proxy server this does not do any load balancing.