jpa/subsystem/src/main/java/org/jboss/as/jpa/processor/JPAAnnotationProcessor.java
private String getClassLevelInjectionType(final AnnotationInstance annotation) {
        boolean isPC = annotation.name().local().equals("PersistenceContext");
        return isPC ? ENTITY_MANAGER_CLASS : ENTITY_MANAGERFACTORY_CLASS;
    }
private String getClassLevelInjectionType(final AnnotationInstance annotation) {
        boolean isPC = annotation.name().local().equals("PersistenceContext");
        return isPC ? ENTITY_MANAGER_CLASS : ENTITY_MANAGERFACTORY_CLASS;
    }
Based on the the annotation type, its either entitymanager or entitymanagerfactory

@param annotation
@return