The blogger has this bug in the code to convert ResultSet to JSON copied from the Internet

 public static String resultSetToJson(ResultSet rs) throws SQLException,JSONException
    {
       // json array
       JSONArray array = new JSONArray();
      
               // Get the number of columns
       ResultSetMetaData metaData = rs.getMetaData();
       int columnCount = metaData.getColumnCount();
      
               // Traverse each piece of data in the ResultSet
        while (rs.next()) {
            JSONObject jsonObj = new JSONObject();
           
                         // loop through each column
            for (int i = 1; i <= columnCount; i++) {
                String columnName =metaData.getColumnLabel(i);
                String value = rs.getString(columnName);
                jsonObj.put(columnName, value);
            } 
                         array.put(jsonObj); //The error is reported in this line The method put(JSONObject) is undefined for the type JSONArray
        }
      
       return array.toString();
    }

After searching a lot of information on the Internet, I found that I only need to change the error line to the following

array.add(jsonObj); 

Reference from stackoverflow
https://stackoverflow.com/questions/26456791/putjsonobject-is-undefined-for-the-type-jsonarray