code: public Object invoke(Object conn, Object requestData) throws AdapterException {
          try {
              DatabaseAccess dbAccess = (DatabaseAccess)conn;
              if (requestData == null)
                  throw new AdapterException("Missing SQL Query");
              String query = (String) requestData;
              QueryType queryType = getQueryType();
  
              Object queryParams = getQueryParameters();
              if (queryParams instanceof List<?>) {
                  if (queryType == QueryType.Select)
                      return dbAccess.runSelect(query, ((List<?>) queryParams).toArray());
                  else if (queryType == QueryType.Update) {
                      Integer ret = new Integer(dbAccess.runUpdate(query, ((List<?>)queryParams).toArray()));
                      dbAccess.commit();
                      return ret;
                  }
                  else
                      throw new AdapterException("Unsupported query type: " + queryType);
              }
              else {
                  if (queryType == QueryType.Select)
                      return dbAccess.runSelect(query, queryParams);
                  else if (queryType == QueryType.Update) {
                      Integer ret = new Integer(dbAccess.runUpdate(query, queryParams));
                      dbAccess.commit();
                      return ret;
                  }
                  else
                      throw new AdapterException("Unsupported query type: " + queryType);
              }
          }
          catch (SQLException ex) {
              AdapterException adapEx = new AdapterException(-1, ex.getMessage(), ex);
              if (isRetryable(ex))
                adapEx.setRetryable(true);
              throw adapEx;
          }
          catch (Exception ex) {
              throw new AdapterException(-1, ex.getMessage() , ex);
          }
      }
docs: Invokes the JDBC Query.
  If QueryType is Select, returns a java.sql.ResultSet.
  If QueryType is Update, returns an Integer with the number of rows updated.