oDesk Enterprise Java Beans (EJB) 2.0 Test 2015

·


1. Which of the following constitute the enhancements made to EJB 2.0?
Answers:
• JMS (Java Message Service) integration
• Improved support for container-managed persistence (CMP)
• Support for RMI/IIOP protocol for network interoperability
• Management of beans relationships
• All of the above

2. A client wants to access Enterprise Java Bean for some processing. The first step will be looking up the class that implements its home interface. Which of the following should be used for the purpose?
Answers:
• JNDI
• MTS
• JTS
• JTA
• Java IDL
3. A pre-cached instance is used to load state information on creation of an EJB.
Answers:
• True
• False
4. What will happen to the running session beans if the EJB container crashes or restarts?
Answers:
• They will get destroyed
• They will keep on running
• Their execution will be halted temporarily
• None of the above
5. An online shop employs a stateless session bean (named 'Eshop') to process the requests. 'Eshop' uses a declarative transaction management system. The following code is from the xml deployment descriptor file of the bean:

1.        <ejb-jar>
2.        <enterprise-beans>
3.         <session>
4.                <ejb-name>Eshop</ejb-name>
5.                <home>com.solution.EshopHome</home>
6.                <remote>com.solution.Eshop</remote>
7.                <local-home>com.solution.EshopLocalHome</local-home>
8.                <local>com.solution.EshopLocal</local>
9.                <ejb-class>com.solution.EshopBean</ejb-class>
10.
11.
12.         </session>
13.        </enterprise-beans>
14.        </ejb-jar>

The session and transaction attributes are to be coded in the lines numbered 10 and 11. Which of the following options should be used to make the bean work as expected?
Answers:
• <session>Stateless</session> <transaction>Container</transaction>
• <session>Stateful</session> <transaction>Bean</transaction>
• <session-type>Stateless</session-type> <transaction-type>Container</transaction-type>
• <session-type>Stateful</session-type> <transaction-type>Bean</transaction-type>
• <session-type>Stateless</session-type> <transaction>Container</transaction>
6. A heavy tool manufacturing company manages its business and production by using enterprise beans. A session bean named 'Status' is used to get the production status for the day. The following code gets the context:

Context initialContext = new InitialContext();

The bean provides a local client view. For the local home interface named 'StatusHome.' What should be the lookup?
Answers:
• StatusHome statusHome = (StatusHome) initialContext.lookup("java:tools/env/ejb/status");
• StatusHome statusHome = Context.lookup("java:tools/env/ejb/status");
• StatusHome statusHome = javax.rmi.PortableRemoteObject.narrow( Context.lookup("java:tools/env/ejb/status"),StatusHome.class);
• StatusHome statusHome = (StatusHome) javax.rmi.PortableRemoteObject.narrow( initialContext.lookup("java:tools/env/ejb/status"),StatusHome.class);

7. Which of the following statements is correct with regard to JavaBeans and Enterprise JavaBeans?
Answers:
• Both can be visible or non-visible at run time
• Both can be deployed as an Active X control
• Both require a Manifest file
• Both have some mechanism to tell the builder-tool/IDE about their functionality
• Both define their deployment descriptors
8. One of the methods of your entity bean retrieves the names of all the patients admitted in a particular ward of a hospital. Using a connection named 'con', you want to execute the following query:

//secId is the parameter received by the method
String query = "SELECT admissionId, patientFirstName, patientLastName FROM ADMISSION WHERE sectionId=" + secId;

Which of the following options will help you execute the query?
Answers:
• Statement stmt=con.createStatement(); ResultSet rs=stmt.executeQuery(query);
• Statement stmt=new Statement(); ResultSet rs=stmt.executeQuery(query);
• Statement stmt=con.createStatement(); ResultSet rs=stmt.execute(query);
• Statement stmt=con.getStatement(); ResultSet rs=stmt.executeQuery(query);
• Statement stmt=con.getStatement(); ResultSet rs=con.executeQuery(query);
9. The following method signature is found in an implemented entity bean named 'CustomerBean.' 'CustomerPK' is a class representing the primary key.

public CustomerPK ejbFindByPrimaryKey(CustomerPK key)
                throws FinderException

By context look up, a client gets the reference to the home object of the above bean, named 'custHome'. It gets the 'CustomerPK' class named 'PK' by a different method. The name of EJBObject is 'Customer', which represents a customer. Which of the following options will you select to invoke the above mentioned method in the client?
Answers:
• Customer = custHome.findByPrimaryKey(PK);
• Customer = custHome.ejbFindByPrimaryKey(PK);
• custHome = custHome.ejbFindByPrimaryKey(PK);
• Customer = findByPrimaryKey(PK);
• PK = custHome.findByPrimaryKey(PK);
10. The EJB specification defines six distinct roles in the application development and deployment life cycle. Which of the following roles is not mentioned in it?
Answers:
• Enterprise Bean Provider
• EJB Developer
• EJB Server Provider
• Application Assembler
• EJB Deployer
• System Administrator
11. The transaction attribute of a bean is set to 'TX_REQUIRES_NEW.' What do you infer about its behavior?
Answers:
• It initiates a new transaction only when the previous one is concluded
• It initiates a new transaction without even waiting for the previous one to conclude
• It sends the request to the EJB container for initiating a new bean
• The bean manages its own transaction
12. Which of the following statements is incorrect with regard to the process of Instance Pooling in EJB?
Answers:
• It increases the overall efficiency of the system
• It facilitates sharing of 'EJB bean instances' among multiple clients
• It is used with stateless session beans
• It is used with entity beans
• None of the above
13. You define an enterprise bean as follows:

Public class CalcSessionBean implements javax.ejb.SessionBean

Which of the following method definitions is not mandatory?
Answers:
• public void ejbCreate() {}
• public void ejbActivate() {}
• public void ejbPassivate() {}
• public void ejbRemove() {}
• public void ejbObject() {}
• public void setSessionContext(SessionContext ctx) {}
14. The principal finder method that must be implemented by every entity bean class is:
Answers:
• ejbFindByPrimaryKey()
• ejbGetByPrimaryKey()
• ejbFindPrimayKey()
• getPrimaryKey()
• getFinder()
15. Which of the following services does an EJB Server/Container provides to EJB?
Answers:
• Life cycle management and Instance pooling
• Activation and Passivation
• Transaction and Security support
• Enforcement of policies and restrictions
• All of the above
16. How do Enterprise Java Beans access the database?
Answers:
• By using Java Database Connectivity
• By using Open Database Connectivity
• Both a and b
• None of the above
17. Which of the following statements is not correct for an Enterprise Java Bean?
Answers:
• Entity beans model business data
• Session beans model business processes
• Message beans send synchronous messages
• None of the above
18. Which of the following transaction modes are supported by Enterprise Java Beans?
Answers:
• TX_NOT_SUPPORTED
• TX_BEAN_MANAGED
• TX_REQUIRED
• TX_MANDATORY
• All of the above
19. Which of the following is not implemented by a stateless session bean?
Answers:
• SessionContext
• SessionSynchronization
• SessionObject
• EJBContext
20. Which of the following statements is not correct with regard to Passivation of beans?
Answers:
• The process is possible in all the enterprise beans
• It is accompanied by some vendor specific methods, which are similar to java serialization
• Both a and b
• None of the above
21. The method ejbCreate() allows session beans to perform initializations. Which of the following methods should be called by the container before ejbCreate()?
Answers:
• newInstance()
• setSessionContext()
• newInstance() and setSessionContext()
• ejbRemove()
22. By interoperating via IIOP, an EJB can directly access:
Answers:
• Existing production systems wrapped in CORBA interface
• Existing production systems wrapped in RMI interface
• Network Technologies
• Messaging Interface
• Language Mapping
23. Which of the following is a name of the design pattern not associated with EJB?
Answers:
• Session Facade
• Entity Command
• Message Facade
• EJB Command
24. An online medical shop uses Container Managed persistent beans for its operations. An OrderBean uses a query to list all the orders where payable amount is more than $800. The XML query tag in the deployment descriptor is as follows:

1. <query>
2.   <query-method>
3.         <method-name>findBigOrders</method-name>
4.        <method-params></method-params>
5.   </query-method>
6.
7. </query>

If the name of the table is 'Order' and total amount payable is in the column named 'amount,' which of the following queries can be placed in line 6?
Answers:
• <ejb-sql>SELECT * FROM Order o WHERE o.amount > 800</ejb-sql>
• <ejb-sql>SELECT OBJECT(o) FROM Order o WHERE o.amount > 800</ejb-sql>
• <ql>SELECT OBJECT(o) FROM Order o WHERE o.amount > 800 </ql>
• <ejb-ql><![CDATA[SELECT OBJECT(o) FROM Order o WHERE o.amount>800 ]]></ejb-ql>
• <ejb-ql>SELECT OBJECT(o) FROM Order o WHERE o.amount > 800 </ejb-ql>
25. The interface that must be implemented by a stateless session bean is javax.ejb.SessionBean.
Answers:
• True
• False
26. Which of the following statements is correct with regard to entity, session, and message-driven beans?
Answers:
• All of them allow sending messages
• All of them must define a remote and home interface
• Both a and b
• None of the above
27. To disable the Passivaton process, set the EJBPassivationTimeout() variable to zero.
Answers:
• True
• False
28. Which of the following statements is correct with regard to 'poison' message?
Answers:
• A JMS destination sends this message to the consumer only once
• It is not acknowledged by the consumer
• JMS destination gets the acknowledgement only once
• The process of sending a 'poison' message is possible with all the enterprise beans
29. The methods declared in Session Bean interface are known as Callback (methods).
Answers:
• True
• False
30. What are the three classes that a Session EJB class must provide?
Answers:
• Home Interface, EJB Remote Interface, and Session context
• EJB class, Home Interface, and EJB Remote Interface
• EJB class, Session context, and EJB Remote Interface
• EJB class, EJB Remote Interface, and Session Synchronization Interface
31. Which of the following statements are correct with regard to EJB QL?
Answers:
• The EJB QL defines finder methods for entity beans with container managed persistence
• EJB QL is introduced in EJB 2.0
• EJB QL is provided for navigation across a network of enterprise beans
• EJB QL is a language that can be compiled
• All of the above
32. SessionSynchronization Interface must be implemented to reset the instance variables.
Answers:
• True
• False
33. Which of the following is a language in which IDL compiler of CORBA generates proxies and skeletons?
Answers:
• Mapping proxies
• Language map
• Language mapping
• Proxy language maps
34. You don't have any database recovery/backup system in place. Which of the following statements is true with regard to committed and uncommitted data of your entity bean?
Answers:
• Committed data cannot survive a server crash
• Neither committed nor uncommitted data survives a server crash
• Both committed and uncommitted data survive a server or database crash
• Both committed and uncommitted data survive a server crash if clustering is used
35. The PrimaryKey class is used to provide each entity bean with a ____________:
Answers:
• Serial identity
• Unique, serializable identity
• Unique identity only
• Not null identity
• Serializable identity only
36. Which of the following services does EJB container provide to a bean?
Answers:
• Support for security
• Support for managing multiple instances
• Support for persistence
• Support for transactions
• All of the above
37. Which of the following statements is correct with regard to the method ejbSelect()?
Answers:
• It is similar to finder method of entity beans
• It is available to the client for querying
• It cannot be used to extract data from other entity beans
• It cannot return entity bean/beans
• It can return values that are defined as CMP-TYPE
38. You are working with EJB2.0. You have to retrieve a previously saved handle to an EJBObject named 'bookEJBObject.' In order to restart the processing for that particular request, you need to get the remote interface. The following code has been written for the same:

1. ObjectInputStream stream =
2.                new ObjectInputStream(new FileInputStream(fileName));
3.
4. Handle bookHandle = (Handle) stream.readObject();
5.
6. BookRemoteInterface bookEjbObject = (BookRemoteInterface) XX() ;

Which of the following should substitute Method XX() of line 6?
Answers:
• javax.rmi.PortableRemoteObject(bookHandle.getEJBObject(), BookRemoteInterface);
• javax.rmi.PortableRemoteObject(EJBObject, BookRemoteInterface);
• javax.rmi.PortableRemoteObject.narraow(bookHandle.getEJBObject(), BookRemoteInterface.class);
• javax.rmi.PortableRemoteObject.narraow(bookHandle, BookRemoteInterface);
• bookHandle.getEJBObject()
39. We are saving a handle to an EJBObject named 'bookEJBObject' for an online book shop:

1. javax.ejb.Handle bookHandle = _____________;
2.
3. ObjectOutputStream stream =
4.                 new ObjectOutputStream(new FileOutputStream(fileName));
5.
6. stream.writeObject(bookHandle);
7. stream.close();

Which of the following methods should be filled in the blank?
Answers:
• (Handle) bookEJBObject()
• bookEJBObject.getHandle()
• bookEJBObject.getEJBHandle()
• newHandleInstance()
40. Both RMI and CORBA define messaging protocols called:
Answers:
• OMP
• JRMP
• IIOP
• JRMP and IIOP
• OMP, JRMP, and IIOP
41. What is the restriction that EJB specification imposes on CMP fields?
Answers:
• They must be public
• They must not be transient
• They must be non-static
• They must be final
• All of the above
42. Database connection pooling is beneficial because:
Answers:
• It avoids the overhead of establishing a new database connection
• Maintaining an open database connection consumes resources on the database
• Both a and b
• ODBC is not required for establishing a connection
43. Which of the following must be implemented by a JMS message-driven bean?
Answers:
• MessageDrivenBean and MessageDrivenContext interfaces
• MessageListener and MessageDrivenBean interfaces
• MessageProducer and MessageDrivenBean interfaces
• ObjectMessage and MessageDrivenBean interfaces
44. Which of the following methods should be invoked by the container to get a bean back to its working state?
Answers:
• EJBPassivate()
• EJBActivate()
• EJBRemove()
• EJBOpen()
• EJBActivation()
45. Which of the following statements is not correct with regard to relationships in EJB?
Answers:
• The tag <relationships> is used by CMP to enclose the relations
• These can be managed by CMP or BMP
• The relationship can be declared in the deployment descriptor
• Directional relationship is always multidirectional