code: private void writeProperties(JsonGenerator jsonGenerator, ResultSet rs) throws IOException, SQLException {
          if (columnCountProperties != -1) {
              jsonGenerator.writeObjectFieldStart("properties");
              for (Map.Entry<String, Integer> entry : cachedColumnNames.entrySet()) {
                  String string = entry.getKey();
                  string = string.toLowerCase();
                  Integer fieldId = entry.getValue();
                  if (rs.getObject(fieldId) instanceof Object[]) {
                      Object[] array = (Object[]) rs.getObject(fieldId);
                      jsonGenerator.writeArrayFieldStart(string);
                      writeArray(jsonGenerator, array, true);
                      jsonGenerator.writeEndArray();
                  } else if (rs.getObject(fieldId) != null && rs.getObject(fieldId).equals("{}")){
                      jsonGenerator.writeObjectFieldStart(string);
                      jsonGenerator.writeEndObject();
                  } else if (rs.getObject(fieldId) == "null") {
                      jsonGenerator.writeFieldName(string);
                      jsonGenerator.writeNull();
                  } else {
                      jsonGenerator.writeObjectField(string, rs.getObject(fieldId));
                  }
              }
              jsonGenerator.writeEndObject();
          }
      }
docs: Write the GeoJSON properties.
  
  @param jsonGenerator
  @param rs
  @throws IOException