docs: @Override
      protected void retrieveBundleContext() {
  
          BundleContext bc = TxBundleTools.getBundleContext();
          if (tc.isDebugEnabled())
              Tr.debug(tc, "retrieveBundleContext from TxBundleTools, bc " + bc);
          if (bc == null) {
              bc = EmbeddableTxBundleTools.getBundleContext();
              if (tc.isDebugEnabled())
                  Tr.debug(tc, "retrieveBundleContext from EmbeddableTxBundleTools, bc " + bc);
          }
          _bc = bc;
      }