JBPM-2964 doesn't solve the original problem explained in the 'Description'.

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In case that commit() throws an exception (e.g. StaleObjectStateException) in DbPersistenceService.endTransaction(), rollback() will be called. And then, if rollback() also throws an exception, a client application will get the latter exception (Usually, it would be java.lang.IllegalStateException: BaseTransaction.rollback - [com.arjuna.ats.internal.jta.transaction.arjunacore.notx] [com.arjuna.ats.internal.jta.transaction.arjunacore.notx] no transaction! ).

  public void endTransaction() {
    if (!isTransactionRollbackOnly()) {
      Exception commitException = commit();
      if (commitException != null) {
        rollback();
        closeSession();
        closeConnection();
        throw new JbpmPersistenceException("transaction commit failed", commitException);
      }
    }
...

It is not a desirable behaviour. It's better to catch the exception on rollback, log it and throw the exception on commit.
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Alejandro seemed to misunderstand my intention. The problem is that the Exception on rollback hides the original Exception on commit.
Please re-consider it.