JBoss Messaging EJB3 Message Driven Bean Example
$Revision: 1459 $
Overview
This example deploys a simple EJB3 Message Driven Bean that processes
messages sent to a test queue. Once it receives a message and
"processes" it, the EJB3 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.
Important! The JBoss instance that runs the
Messaging server must also have EJB3 support previously installed. If
the EJB3 support is not installed, the example will fail with an error
message similar to:
C:\work\src\cvs\jboss-head\jms\docs\examples\ejb3mdb\build.xml:60: EJB3
does not seem to be installed in
C:\work\src\jboss-4.0.3-src\build\output\jboss-4.0.3/server/messaging! Install it and try again.
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For instructions on how to install EJB3 support, please go to http://docs.jboss.org/ejb3/ or
use the JBoss Installer.
Note: The current example was
tested with the EJB3 release bundled with JBoss
4.0.5. Earlier EJB3 versions may use slightly different APIs
that may break
the example. If this is the case, please modify the example
accordingly. Most likely, you will only need to modify the import fully
qualified class names.
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\ejb3mdb
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 EJB3 MDB
example
X
[echo]
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
[echo] The queue: testQueue
sanity-check:
init:
[mkdir] Created dir:
C:\work\src\cvs\jboss-head\jms\docs\examples\ejb3mdb\output\classes\META-INF
[mkdir] Created dir:
C:\work\src\cvs\jboss-head\jms\docs\examples\ejb3mdb\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\ejb3mdb\output\classes
jar:
[jar] Building jar:
C:\work\src\cvs\jboss-head\jms\docs\examples\ejb3mdb\output\lib\mdb-example.ejb3
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.GA (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.ejb3
BUILD SUCCESSFUL
Total time: 10 seconds
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Troublesooting
1. While compiling the example I get
C:\work\src\cvs\jboss-head\jms\docs\examples\ejb3mdb\src\org\jboss\examples\jms\ejb3mdb\EJB3MDBExample.java:29:
illegal character: \64
@MessageDriven(activateConfig =
^
You're compiling with Java 4. You need to use Java 5 in order to
be able to compile and take advantage of annotations.
2. 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.
3. 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/testQueue exists
[java] The Hello! message was successfully sent to the testQueue 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.