This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
the followign question's answer in a mock test was incorrect.
The Enterprise JavaBean 2.0 specification has introduced the notion of local Clients. What are Local Clients and why were they introduced?
Answer is C and F. Which is wrong. It should be B and E.
A Local Clients should be used when the web server is running on the same machine as the application server.
B Local Clients should be used when Session Beans need to communicate with Entity Beans.
Beans in the same Virtual Machine should use local Clients.
C Local Clients have been introduced to make testing code easier.
D Local Clients have been introduced to improve maintainability.
E Local Clients have been introduced to improve performance.
F Local Clients should be used when the database is running on the same machine as the application server.
Choices C and F are correct.
Note: This type of question will not be in the EJB 1.1 version of the SCEA but is likely to be in the EJB 2.0 version of the SCEA.Prior to the Enterprise JavaBean 2.0 specification all Bean clients were seen as remote clients. This meant that if a Session Bean needed to talk to an Entity Bean inside the same Virtual Machine it would still need to make a remote call. This obviously had a direct impact on performance. In EJB 2.0 Enterprise Beans can now treat other beans in the same VM as local clients. Local Clients can access the beans through its local and local home interfaces.Remote clients use pass-by-value but Local clients use pass-by-reference.For more information please see:http://java.sun.com/products/ejb/2.0.html