@Transactional
public boolean generateLogsComposite() {
    Connection conn = getConnection();
    writeSomeData(conn);//write some data using a separate connection
    boolean isNew = checkSomeData();//The check works with the data from writeSomeData although not using he connection conn
    if(isNew) {
        generateEmail(conn);//Calls a stored procedure on connection conn.
        updateRunEnvOnEmail(emailId, runEnv);
        //Now the data from generateEmail and updateRunEnvOnEmail is present
    } else {
        updateSomething();//has a javax.persistence.TransactionRequiredException: Executing an update/delete query
    }
}

private void joinTransaction() {
    try {
        //HACK vs javax.persistence.TransactionRequiredException: Executing an update/delete query
        entityManager.joinTransaction();
        logger.debug("Joined transaction successfully");
    } catch(Throwable t) {
        //java.lang.IllegalStateException: Not allowed to join transaction on shared EntityManager
    }
}

@Transactional
public void updateRunEnvOnEmail(Long emailId, String runEnv)
{
    try
    {
        //HACK vs javax.persistence.TransactionRequiredException: Executing an update/delete query
        joinTransaction();

        Query query = entityManager
                .createNativeQuery("update XXX.EMAIL e set e.RUN_ENVIRONMENT = :runEnv where e.EMAIL_ID = :emailId");
        query.setParameter("runEnv", runEnv);
        query.setParameter("emailId", emailId);
        query.executeUpdate();
    } catch (Exception e)
    {
        logger.debug("Error while updating RUN_ENVIRONMENT on Email : "
                + emailId + " ::: " + e);
    }

}

@Transactional
public void updateSomething()
{
    try
    {
        //HACK vs javax.persistence.TransactionRequiredException: Executing an update/delete query
        joinTransaction();

        Query query = entityManager
                .createNativeQuery("update something");
        query.executeUpdate();
    } catch (Exception e)
    {
        logger.debug("Error while updating something",e);
    }

}