"JBAS011470: Persistence unitName was not specified and there are 2 persistence unit definitions ..." in JBoss EAP

Issue

• Multiple persistence units are defined in a single persistence.xml included in an EAR
• At deployment of the EAR, the following exception is raised:

JBAS011470: Persistence unitName was not specified and there are 2 persistence unit definitions in application deployment deployment "test.ear".  Either change the application deployment to have only one persistence unit definition or specify the unitName for each reference to a persistence unit.
        at org.jboss.as.jpa.container.PersistenceUnitSearch.ambiguousPUError(PersistenceUnitSearch.java:171)
        at org.jboss.as.jpa.container.PersistenceUnitSearch.findWithinDeployment(PersistenceUnitSearch.java:151)
        at org.jboss.as.jpa.container.PersistenceUnitSearch.findPersistenceUnitSupplier(PersistenceUnitSearch.java:74)
        at org.jboss.as.jpa.container.PersistenceUnitSearch.resolvePersistenceUnitSupplier(PersistenceUnitSearch.java:63)
        at org.jboss.as.jpa.processor.JPAAnnotationProcessor.getPersistenceUnit(JPAAnnotationProcessor.java:358)
        at org.jboss.as.jpa.processor.JPAAnnotationProcessor.getBindingSource(JPAAnnotationProcessor.java:289)
        at org.jboss.as.jpa.processor.JPAAnnotationProcessor.processField(JPAAnnotationProcessor.java:167)
        at org.jboss.as.jpa.processor.JPAAnnotationProcessor.processPersistenceAnnotations(JPAAnnotationProcessor.java:134)
        at org.jboss.as.jpa.processor.JPAAnnotationProcessor.deploy(JPAAnnotationProcessor.java:96)
        at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:159)
        ...