code: public void clearTableState(String key) {
          Map<String, Object> sessionMap = getFacesContext().getExternalContext().getSessionMap();
          Map<String, TableState> dtState = (Map) sessionMap.get(Constants.TABLE_STATE);
          if (dtState != null) {
              dtState.remove(key);
          }
      }
docs: Removes the multiViewState for one specific DataTable within the current session.
  @param key Key of the DataTable. See {@link org.primefaces.component.datatable.DataTable#getTableState(boolean)} for the namebuild of this key.