title: PersistenceUnit already registered
body: <p>While trying to deploy my war file into Jboss 6.4 server I am getting the following error, I googled it but mostly every one says make sure you are running single instance of Jboss, I am running single instance of Jboss and single deployment</p>
  
  <blockquote>
    <p>21:00:48,747 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-2) MSC000001: Failed to start service jboss.deployment.unit."msp-collectorder-service-17.9.0.war".INSTALL: org.jboss.msc.service.StartException in service jboss.deployment.unit."msp-collectorder-service-17.9.0.war".INSTALL: JBAS018733: Failed to process phase INSTALL of deployment "msp-collectorder-service-17.9.0.war"<br>
        at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:166) [jboss-as-server-7.4.0.Final-redhat-19.jar:7.4.0.Final-redhat-19]<br>
        at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1980) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1913) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [rt.jar:1.8.0_161]<br>
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [rt.jar:1.8.0_161]<br>
        at java.lang.Thread.run(Thread.java:748) [rt.jar:1.8.0_161]
    Caused by: org.jboss.as.server.deployment.DeploymentUnitProcessingException: JBAS011446: Failed to add persistence unit service for orderPersistenceUnit<br>
        at org.jboss.as.jpa.processor.PersistenceUnitServiceHandler.deployPersistenceUnit(PersistenceUnitServiceHandler.java:447)<br>
        at org.jboss.as.jpa.processor.PersistenceUnitServiceHandler.addPuService(PersistenceUnitServiceHandler.java:275)<br>
        at org.jboss.as.jpa.processor.PersistenceUnitServiceHandler.handleWarDeployment(PersistenceUnitServiceHandler.java:190)<br>
        at org.jboss.as.jpa.processor.PersistenceUnitServiceHandler.deploy(PersistenceUnitServiceHandler.java:116)<br>
        at org.jboss.as.jpa.processor.PersistenceCompleteInstallProcessor.deploy(PersistenceCompleteInstallProcessor.java:48)<br>
        at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:159) [jboss-as-server-7.4.0.Final-redhat-19.jar:7.4.0.Final-redhat-19]<br>
        ... 5 more<br>
    Caused by: org.jboss.msc.service.DuplicateServiceException: Service jboss.persistenceunit."msp-collectorder-service-17.9.0.war#orderPersistenceUnit" is already registered<br>
        at org.jboss.msc.service.ServiceRegistrationImpl.setInstance(ServiceRegistrationImpl.java:158) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at org.jboss.msc.service.ServiceControllerImpl.startInstallation(ServiceControllerImpl.java:236) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at org.jboss.msc.service.ServiceContainerImpl.install(ServiceContainerImpl.java:742) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:243) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:2433) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:243) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:2433) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at org.jboss.msc.service.ServiceBuilderImpl.install(ServiceBuilderImpl.java:345) [jboss-msc-1.1.5.Final-redhat-1.jar:1.1.5.Final-redhat-1]<br>
        at org.jboss.as.jpa.processor.PersistenceUnitServiceHandler.deployPersistenceUnit(PersistenceUnitServiceHandler.java:441)<br>
        ... 10 more  </p>
  </blockquote>
  
  <p>Any help is greatly appreciated as I am stuck with this for a long time.</p>