JTA does not write to database with wildfly

Question

I try to write database usign container managed jta with wildfly 10 application server. It gives no errors but writes nothing to database.

This is my persistence.xml file:

<persistence-unit name="myPersistenceUnit" transaction-type="JTA">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <jta-data-source>java:/datasources/myOracleDataSource</jta-data-source>
</persistence-unit>

My class is:

@TransactionManagement(TransactionManagementType.CONTAINER)
public class UserDaoImpl implements UserDao {   
    @PersistenceContext(unitName="myPersistenceUnit")
    EntityManager userEM;

    public UserDaoImpl (EntityManager userEM) {
        this.userEM = userEM;
    }

    @Transactional(Transactional.TxType.REQUIRES_NEW)
    public int createNewUser(int id, String name) {
        User user = new User(id, name);
        userEM.persist(user);   
    }
}

When I try to write second time it throws unique index exception. However, after restart the server it gives again no errors. I think it holds changes in memory but not writes to database.

I have stucked with this issue. Do you have any idea?