# JBoss Messaging Message Driven Bean Example

$Revision: 1.7 $

## Overview

This example deploys a simple Message Driven Bean that processes messages sent to a test queue. Once it receives a message and "processes" it, the MDB sends an acknowledgment message to a temporary destination created by the sender for this purpose. The example is considered successful if the sender receives the acknowledgment message.
This example relies on having access to a running JBoss Messaging instance. The JBoss Messaging instance must be installed and started according to the "Installation" paragraph from the release documentation. However, the example will automatically deploy its own queue, unless a queue with the same name is already deployed.
This example also relies on having access to jboss-messaging-client.jar archive that comes with the release bundle. If you run this example from an unzipped installation bundle, the example run script is correctly configured to find the client jar. Otherwise, you must modify example's build.xml accordingly.
The example was designed to deploy its server-side artifacts under a JBoss' messaging configuration. If you intend to use the script with a JBoss configuration that is named differently, please modify the example's build.xml accordingly.

## Running the example

1. Set up the JBOSS_HOME environment variable to point to the JBoss instance you deployed JBoss Messaging into. For example, if you deployed JBoss Messaging in C:\jboss-4.0.3SP1\server\default\deploy, then your JBOSS_HOME value should be C:\jboss-4.0.3SP1.
2. Go to the example's home directory
cd ...\examples\mdb
3. Run the example:
ant
The output of a successful run should be similar to:

$ ant Buildfile: build.xml identify: [echo] XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX [echo] X Running the MDB example X [echo] XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX [echo] The queue: testQueue sanity-check: init: [mkdir] Created dir: C:\work\src\cvs\jboss-head\jms\docs\examples\mdb\output\classes\META-INF [mkdir] Created dir: C:\work\src\cvs\jboss-head\jms\docs\examples\mdb\output\lib\META-INF [mkdir] Created dir: C:\work\src\cvs\jboss-head\jms\docs\examples\common\output compile: [javac] Compiling 2 source files to C:\work\src\cvs\jboss-head\jms\docs\examples\common\output [javac] Compiling 2 source files to C:\work\src\cvs\jboss-head\jms\docs\examples\mdb\output\classes jar: [copy] Copying 2 files to C:\work\src\cvs\jboss-head\jms\docs\examples\mdb\output\classes\META-INF [jar] Building jar: C:\work\src\cvs\jboss-head\jms\docs\examples\mdb\output\lib\mdb-example.jar deploy: [copy] Copying 1 file to C:\work\src\jboss-4.0.3SP1-src\build\output\jboss-4.0.3SP1\server\messaging\deploy sleep: [echo] Sleeping for 5 seconds ... run: send: [java] Queue /queue/testQueue exists [java] The Hello! message was successfully sent to the testQueue queue [java] Received message: !olleH [java] The example connected to JBoss Messaging version 1.0.1.CR3 (1.0) [java] ##################### [java] ### SUCCESS! ### [java] ##################### undeploy: [delete] Deleting: C:\work\src\jboss-4.0.3SP1-src\build\output\jboss-4.0.3SP1\server\messaging\deploy\mdb-example.jar BUILD SUCCESSFUL Total time: 10 seconds

## Troublesooting

### 1. I get "javax.jms.JMSSecurityException: User null is NOT authenticated"

You probably didn't install JBoss Messaging correctly. A fresh JBoss Messaging installation requires changes in the security configuration of a default JBoss instance, specifically a properly configured "messaging" security domain. Follow the instructions from the "Installation" paragraph of the release documentation.
2. The example fails with "Have not received any reply. The example failed!" and the server log contains ClassNotFoundExceptions
If all you get after running the example is
send:
[java] Queue /queue/SmokeTestQueue exists
[java] The Hello! message was successfully sent to the SmokeTestQueue queue
[java] java.lang.Exception: Have not received any reply. The example failed!
[java] at org.jboss.example.jms.mdb.Sender.example(Sender.java:102)
[java] at org.jboss.example.jms.common.ExampleSupport.run(ExampleSupport.java:58)
[java] at org.jboss.example.jms.mdb.Sender.main(Sender.java:131)
[java] #####################
[java] ### FAILURE! ###
[java] #####################
check the server log. The presence of
2006-04-11 17:14:58,370 DEBUG [org.jboss.ejb.plugins.jms.DLQHandler] Initialization failed DLQHandler
javax.naming.CommunicationException [Root exception is java.lang.ClassNotFoundException: No ClassLoaders found for: org.jboss.jms.client.JBossConnectionFactory (no security manager: RMI class loader disabled)]
at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:713)
at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:572)
at javax.naming.InitialContext.lookup(InitialContext.java:347)
at org.jboss.ejb.plugins.jms.DLQHandler.createService(DLQHandler.java:151)
at org.jboss.system.ServiceMBeanSupport.jbossInternalCreate(ServiceMBeanSupport.java:245)
at org.jboss.system.ServiceMBeanSupport.create(ServiceMBeanSupport.java:173)
...
means that your Naming service was configured with a CallByValue semantics. There are two solutions for this situation:
1) Enable JNDI call by reference semantics.
To do that, modify the Naming (JNDI) service configuration and set its "CallByValue" attribute to "false".
The Naming configuration file is $JBOSS_HOME/server/default/deploy/naming-service.xml for an installer-generated JBoss configuration and $JBOSS_HOME/server/conf/jboss-service.xml (the JNDI section, search for "jboss:service=Naming") for a raw installation.
2) In case you don't want to change JNDI CallByValue semantics, deploy the MDB in the same class loading domain as the Messaging server.