output: #fixed code
                                public static List<Object[]> queryGenericObjectArrayListSQL(String poolName, String sql, Object[] params) {
  
      List<Object[]> returnList = null;
  
      try {
  
        ArrayListHandler resultSetHandler = new ArrayListHandler();
        // returnList = new QueryRunner().query(con, sql, resultSetHandler, params);
        returnList = new QueryRunner(DB_CONNECTION_MANAGER.getDataSource(poolName)).query(sql, resultSetHandler, params);
  
      } catch (Exception e) {
        logger.error(QUERY_EXCEPTION_MESSAGE, e);
      }
  
      return returnList;
    }
input: #vulnerable code 
                                public static List<Object[]> queryGenericObjectArrayListSQL(String poolName, String sql, Object[] params) {
  
      List<Object[]> returnList = null;
  
      Connection con = null;
  
      try {
        con = DB_CONNECTION_MANAGER.getConnection(poolName);
  
        if (con == null) {
          throw new ConnectionException(poolName);
        }
  
        con.setAutoCommit(false);
  
        ArrayListHandler resultSetHandler = new ArrayListHandler();
        returnList = new QueryRunner().query(con, sql, resultSetHandler, params);
  
        con.commit();
      } catch (Exception e) {
        logger.error(QUERY_EXCEPTION_MESSAGE, e);
        try {
          con.rollback();
        } catch (SQLException e1) {
          logger.error(ROLLBACK_EXCEPTION_MESSAGE, e1);
        }
      } finally {
        DB_CONNECTION_MANAGER.freeConnection(con);
      }
  
      return returnList;
    } 
                              #location 23 
                              #vulnerability type NULL_DEREFERENCE