O'Reilly logo

Head First Servlets and JSP, 2nd Edition by Bert Bates, Bryan Basham, Kathy Sierra

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Memorizing the EJB-related DD tags

This exam is about web components, not business components (although in the Patterns chapter, you’ll see a few things about business components). But if you’re deploying a J2EE app, complete with Enterprise JavaBeans (EJBs) in the business tier, some of your web components will probably need to lookup and access the enterprise beans. If you’re deploying an app in a full J2EE-compliant Container (one that has an EJB Container as well), you can define references to EJBs in the DD. You don’t have to know anything about EJBs for this exam, other than what you declare in the DD, so we won’t waste your time explaining it here.[11]

Reference to a local bean

image with no caption
image with no caption

A LOCAL bean means the client (in this case, a servlet) and the bean must be running in the same JVM.

Reference to a remote bean

<ejb-ref>
   <ejb-ref-name>ejb/LocalCustomer</ejb-ref-name>
   <ejb-ref-type>Entity</ejb-ref-type>
   <home>com.wickedlysmart.CustomerHome</home>
   <remote>com.wickedlysmart.Customer</remote>
</ejb-ref>
image with no caption

A REMOTE bean means the client (in this case, a servlet) and the bean can be running in different JVMs (possibly on different physical machines as well).

Note

(Optional sub-elements for both tags ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required