docs: private void beginInternTransaction()
      {
          if (log.isDebugEnabled()) log.debug("beginInternTransaction was called");
          J2EETransactionImpl tx = (J2EETransactionImpl) super.currentTransaction();
          if (tx == null) tx = newInternTransaction();
          if (!tx.isOpen())
          {
              // start the transaction
              tx.begin();
              tx.setInExternTransaction(true);
          }
      }