How to force commit transaction of EntityManager

Question

I have the following case in a web app:

@Stateless
@LocalBean
public class AccountBean {
   
    @PersistenceContext(unitName = "foreign-context")
    private EntityManager fem;
    @PersistenceContext(unitName = "own-context")
    private EntityManager oem;

    public void doCreate() {
        Account account = createAccount();
        SubAccount subAccount = createSubAccount(account);
    }

    private Account createAccount() {
       Account account = new Account("This is a sample");
       oem.persist(account);
       oem.flush();
       return oem;
    }

    private SubAccount createSubAccount(Account account) {
       SubAccount subAccount = new SubAccount(account.getId()); // This field is only set after Account entity is persisted
       fem.persist(subAccount);
       fem.flush();
       return subAccount;
    }
} 

The problem as I see it is that account.getId() returns the default value 0 (as is int) causing SQL exception when attempting to save SubAccount due to table constraints. The ID field on account is supposed to be set after the Account is persisted however I suspect that due to the uncommitted transactions the result is not persisted, therefore the ID field is not updated in code. I have tested both of the methods individually and they seem to work fine but when combined the issue arises.

I have to use two separate EntityManager(s) due to business requirements having the model objects in different project dependencies each with it's own descriptor.

I have tried creating a new container managed transaction using @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW) on createAccount() but to no avail.

The code runs on a Wildfly Server using Hibernate 5.2.4 if that's relevant. No other framework is used (except JPA)

How can I alleviate this issue?

Answer 1

Do not completely understand your code, method persist should return you object with id and you can use it.