A Java Persistence application wants to use optimistic locking. Which statement that describes the functionality of optimistic locking is correct?
A. The Version attribute of an entity using optimistic locking can be mapped to a secondary table.
B. Optimistic locking can be used by Java Persistence applications to set optimistic locks on tables in the database.
C. The Version attribute of an entity using optimistic locking is verified each time the instance is loaded from the database.
D. Optimistic locking ensures that updates or deletes are consistent with the current state of the database and that intervening updates are not lost.
A company has a business application that allows end users to order products over the web. A developer in the company wants to add the following capability to the application:
When the web-tier handles a new order, it should notify all the interested beans in the EJB-tier. To satisfy this new capability, the developer wants to use a message-driven bean and must choose between associating it with a javax.jms.Topic
destination or a javax.jms.Queue destination. Which two are true about this decision? (Choose two.)
A. JMS Topics are intendedtobe usedtosolvethistype of scenario.
B. JMS Queues areintendedto be used to solvethistype of scenario.
C. OnlyQueue destinations allow for messages tosurvivea server crash.
D. Topic destinationsallowthe developer to configure subscription durability.
Consider the following classes: 11.©Entity Auction {
12.
@ld int id;
13.
@OneToOne Item item;
14.}
11.©Entity Itemj
12.
@ld int id;
13.
@OneToOne (mappedBy="item") Auction auction;
14.
}
Given that the Auction entity maps to an AUCTION database table and the Item entity maps to an ITEM database table, which statement is correct assuming there is NO mapping descriptor?
A. The relationship is mapped to a foreign key in the ITEMtable.
B. Therelationship is mapped usingajointableAUCTIONJTEM.
C. The relationship is mappedtoaforeignkeyinthe AUCTIONtable.
D. The relationshipis mapped to foreignkeysinbothITEMandAUCTION tables.
The bean class of an EJB Web service endpoint has one method annotated with @WebMethod. Which two types can be legally returned from that method? (Choose two.)
A. Java. util. Date
B. javax.ejb.Timer
C. an array ofJava.lang. String
D. an EJB3.0local businessinterfacereference
E. an EJB3.0 remotebusiness interfacereference
Bean A is using bean-managed transaction demarcation and has invoked the foo method of bean B. When the foo method returns, bean A needs to determine if the transaction has been set to rollback. Which must be true?
A. It is NOT possible for bean A to determine if the transaction has been set to rollback.
B. Bean A must invoke the getStatus method on the UserTransaclion that it began.
C. For this to be possible, bean B must also use bean-managed transaction demarcation.
D. Bean A must invoke the setRollbackOnly method on the UserTransaction that it began.
E. Bean A must invoke the getRollbackOnly method on the UserTransaction that it began.
The execution of the find method in the following code throws an exception:
11.
em.find(Customer.class, custld);
12.
//Where em is a reference to a extended scoped entity manager. Which scenario can cause the exception?
A. Thefindmethod was called without a transaction.
B. Theentity corresponding to therequestedprimary key has been removed.
C. The entity corresponding to therequestedprimarykeyhas beendetached.
D. The data type of custld is NOT a valid type fortheCustomer entity primary key.
A developer's objective is to end the persistence context associated with an application- managed entity manager. Which statement is correct?
A. Invoke the flush method of theentitymanager.
B. Invoke the close method of the entity manager.
C. Invokethe clear methodofthe entity manager.
D. Invoke the remove method of the entity manager.
Given the following code snippet from an EJB 3.0 entity class:
1.
package com.foo;
2.
// more code here... 10.©Entity
11.
@Table(name="A")
12.
public class Order {
And the following excerpt from the persistence unit's orm.xml mapping file:
10.
11.