= Steps to reproduce =
1. Create a jar containing a META-INF/persistence.xml file.
2. Set the persistence-unit@name attribute to 'test'.
3. Wrap the jar inside an ear archive -> 'foo.ear'
4. Deploy the ear to jBoss -> works ok.
5. Rename the ear to 'bar.ear'
6. Deploy to jBoss -> javax.management.InstanceAlreadyExistsException is thrown, stack trace follows:

16:29:05,285 WARN [AbstractDeploymentContext] Unable to register deployment mbean org.jboss.metadata.jpa.spec.PersistenceUnitMetaData.test
javax.management.InstanceAlreadyExistsException: jboss.deployment:id="org.jboss.metadata.jpa.spec.PersistenceUnitMetaData.test",type=Component already registered.
at org.jboss.mx.server.registry.BasicMBeanRegistry.add(BasicMBeanRegistry.java:767)
at org.jboss.mx.server.registry.BasicMBeanRegistry.registerMBean(BasicMBeanRegistry.java:236)
at sun.reflect.GeneratedMethodAccessor90.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:157)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:96)
at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:138)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:90)
at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:140)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:90)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668)
at org.jboss.mx.server.MBeanServerImpl$3.run(MBeanServerImpl.java:1431)
at java.security.AccessController.doPrivileged(Native Method)
at org.jboss.mx.server.MBeanServerImpl.registerMBean(MBeanServerImpl.java:1426)
at org.jboss.mx.server.MBeanServerImpl.registerMBean(MBeanServerImpl.java:376)
at org.jboss.deployers.structure.spi.helpers.AbstractDeploymentContext.registerMBeans(AbstractDeploymentContext.java:990)
at org.jboss.deployers.structure.spi.helpers.AbstractDeploymentContext.addComponent(AbstractDeploymentContext.java:719)
at org.jboss.deployers.structure.spi.helpers.AbstractDeploymentUnit.addComponent(AbstractDeploymentUnit.java:249)
at org.jboss.jpa.deployers.AbstractDeploymentVisitor.addComponent(AbstractDeploymentVisitor.java:49)
at org.jboss.jpa.deployers.AbstractDeploymentVisitor.deploy(AbstractDeploymentVisitor.java:64)
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployerWithInput.deploy(AbstractRealDeployerWithInput.java:125)
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployerWithInput.internalDeploy(AbstractRealDeployerWithInput.java:102)
at org.jboss.deployers.spi.deployer.helpers.AbstractComponentDeployer.internalDeploy(AbstractComponentDeployer.java:78)
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployer.deploy(AbstractRealDeployer.java:50)
at org.jboss.deployers.plugins.deployers.DeployerWrapper.deploy(DeployerWrapper.java:171)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doDeploy(DeployersImpl.java:1439)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1157)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1210)
at org.jboss.deployers.plugins.deployers.DeployersImpl.install(DeployersImpl.java:1098)
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1598)
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1062)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
at org.jboss.deployers.plugins.deployers.DeployersImpl.process(DeployersImpl.java:781)
at org.jboss.deployers.plugins.main.MainDeployerImpl.process(MainDeployerImpl.java:698)
at org.jboss.system.server.profileservice.hotdeploy.HDScanner.scan(HDScanner.java:290)
at org.jboss.system.server.profileservice.hotdeploy.HDScanner.run(HDScanner.java:221)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:181)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:205)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:619)

= Expected Behaviour =
Include the container name in the mbean id:

• org.jboss.metadata.jpa.spec.PersistenceUnitMetaData.foo.test
• org.jboss.metadata.jpa.spec.PersistenceUnitMetaData.bar.test