jpa/subsystem/src/main/java/org/jboss/as/jpa/transaction/TransactionUtil.java
public static void putEntityManagerInTransactionRegistry(String scopedPuName, EntityManager entityManager, TransactionSynchronizationRegistry tsr) {
        tsr.putResource(scopedPuName, entityManager);
    }
public static void putEntityManagerInTransactionRegistry(String scopedPuName, EntityManager entityManager, TransactionSynchronizationRegistry tsr) {
        tsr.putResource(scopedPuName, entityManager);
    }
Save the specified EntityManager in the local threads active transaction.  The TransactionSynchronizationRegistry
will clear the reference to the EntityManager when the transaction completes.

@param scopedPuName
@param entityManager