jpa/subsystem/src/main/java/org/jboss/as/jpa/container/CreatedEntityManagers.java
public static void registerPersistenceContext(ExtendedEntityManager xpc) {
        if (xpc == null) {
            throw JpaLogger.ROOT_LOGGER.nullParameter("SFSBXPCMap.RegisterPersistenceContext", "EntityManager");
        }
        final List<ExtendedEntityManager> store = deferToPostConstruct.get();
        store.add(xpc);
    }
public static void registerPersistenceContext(ExtendedEntityManager xpc) {
        if (xpc == null) {
            throw JpaLogger.ROOT_LOGGER.nullParameter("SFSBXPCMap.RegisterPersistenceContext", "EntityManager");
        }
        final List<ExtendedEntityManager> store = deferToPostConstruct.get();
        store.add(xpc);
    }
At injection time of a XPC, register the XPC (step 1 of 2)
finishRegistrationOfPersistenceContext is step 2

@param xpc The ExtendedEntityManager