Quiz for EJB Tutorial
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1. What does the EJB specification architecture define ? Transactional components Distributed object components components Server-side components All of the above 2. What executes EJB components ? A web server An application server server An EJB container A database server server 3. What do enterprise beans use to communicate with the EJB container to get runtime context information ? The javax.ejb.EJBContext provided by the container A JNDI ENC context A javax.ejb.EJBHome javax.ejb.EJBHome object provided provided by the container container A javax.ejb.EJBMetaData javax.ejb.EJBMetaData object provided provided by the container container 4. Through what interface does an application create, find, and remove enterprise beans ? java.rmi.Remote java.rmi.Remote javax.ejb.EJBHome javax.ejb.EJBHome javax.ejb.EJBObject javax.ejb.EntityBean javax.ejb.EntityBean 5. What type of enterprise bean is used to embody business objects ? javax.ejb.EnterpriseBean javax.ejb.EnterpriseBean
java.rmi.Remote javax.ejb.SessionBean javax.ejb.EntityBean 6. What type of enterprise bean is used to embody application processing state information ? javax.ejb.EnterpriseBean javax.rmi.Remote javax.ejb.SessionBean javax.ejb.EntityBean 7. What interface must the enterprise bean implement so that an application can invoke its operations ? javax.ejb.EntityBean javax.ejb.EJBHome javax.rmi.Remote javax.ejb.EJBObject 8. At what point, precisely, in the life-cycle is a container-managed entity bean considered created ? Immediately prior to the execution of its ejbCreate() method Immediately after the execution of its ejbCreate() method After the CMP bean's data has been committed to the underlying persistent datastore During the execution of its ejbPostCreate() method 9. What distinguishes a bean-managed persistent (BMP) enterprise bean from a containermanaged persistent (CMP) enterprise bean ? A BMP bean must implement the ejbLoad() and ejbStore() methods A BMP bean can implement persistence to custom datastores such as legacy systems A BMP bean is responsible for managing its own persistence to a persistent datastore All of the above
10. What is a deployment descriptor ? An XML file format used by the container to learn about the attributes of a bean, such as transactional characteristics and access control A method for transporting enterprise beans back and forth between systems An XML file used by enterprise bean clients to learn about the attributes of a bean, such as access control and transactional characteristics. A format for bundling enterprise beans for delivery to customers. 11. A stateless session bean: Is created when the client invokes sreate on the home There must be one per client as long as the client is executing the business logic. Is the most scalable type of bean B and C are correct 12. What happens when you pass a serialized object as an argument or return value that doesn't exist either in the Client or the Server ? Nothing will happpen. An error will occur A run time exception is produced none of these 13. When you pass a Remote object to or from a remote method, what is really passed ? The Remote object reference A local copy of the remote object. None of these The Remote object's stub 14. When a bean moves from the "does not exist" to the "method ready" status, in which order do the events take place ? construction,ejbCreate(),setSessionContext() construction,setSessionContext(),ejbCreate()
setSessionContext() only take place. None of these. 15. What is true for the isIdentical() method of the EJBObject interface for stateless session beans ? Returns true if the stubs refferring to two different Remote EJB objects. Create the session bean. All of the above. None of these. 16. A Message-driven bean: Has a client view Doesn't feature a component interface. Has a Remote interface Has a local interface 17. An entity bean: can be shared between multiple clients as long as the entity being shared is same. Must have its EJBObject interface. A and B are correct. None of these. 18. Is an entity bean allowed to return objects that don't implement the component interface ? Yes. No. Yes but only if they implement EJBHome interface Yes but only if they are RMI-IIOP types 19. What would you do in the constructor of a stateful session bean ? Access the beans JNDI environment.
Get a reference to the bean's home. Just nothing. None of these. 20. For remote objects Java passes objects: By reference. By object copy. By producing a serialized copy. B and C are correct. Answers
1. D 2. C 3. A 4. B 5. D 6. C 7. D 8. B 9. D 10. A 11. D 12. C 13. D 14. B 15. A 16. B 17. C 18. D 19. C 20. D
