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with the created connection and  mdb subscription id  is the name of the durable

subscription to be used.

In the  onMessage()  method you can access another EJB, a resource like a database, mail or

send a copy or a new message to another destination. Please take into consideration that it

is up to the application server how many instances of the same MDB it creates as it is with

SLSB. Therefore processing of messages can be concurrently and out of order. So you could

receive a  place order  message before  create order  message.

Web Applications

Web applications are running inside the JBoss application server. So they have access to the

container reserved JNDI namespace  java:/comp  but can also refer to other EJBs deployed

on the same application server. Because the JBoss web servers are running within the same

JVM its servlets (at runtime JSPs are servlets as well) can access all the resources in JBoss

locally.

The DTD of the JBoss specific DD  jboss web.xml  is defined as:

   security domain?, context root?, virtual host?,

   resource env ref*, resource ref* , ejb ref*

)>

The  context root  allows you to specify another document root for the standalone web

application but do not overwrite a document root in the Enterprise application DD

 application.xml . The  virtual host  allow you to specify to which virtual host this

application is deployed too. Finally the  resource ref  and  ejb ref  allows you to specify the

references to resources and EJBs deployed on this server, which then later on can be

renamed by the deployer if necessary.

A Web application is typically deployed as WAR file that is nothing else than a regular Java

archive (JAR) with a different extension. It can contain the Web application DD  web.xml

as well as the JBoss specific DD  jboss web.xml . Note that these files must be added to the

 WEB INF' directory instead of the  META INF . Due the fact that a Web application is a

client to EJBs, if used, you have to add the Java archive containing the client EJB classes

into either the  WEB INF/lib  or  WEB INF/classes  directory.

Enterprise Applications

Enterprise applications are just a convenience package containing EJB applications, Web

applications and client EJB archives so that it can be deployed as single file. Currently there

is no additional features and therefore also no JBoss specific deployment descriptor for the

Enterprise applications.

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