SortJSON.java

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Map;
import java.util.TreeMap;

/**
 * Author: Javier Benek
 * Just a simple test to sort the elements of a JSON document using TreeMap instead of LinkedHashMap
 */

public class SortJSON {

    private final static Logger LOGGER = LoggerFactory.getLogger(SortJSON.class);

    public void doSort(){

        final JSONParser parser = new JSONParser();
        final String jsonFileToLoad = "/path/to/file.json";

        try {
            final JSONObject json = (JSONObject) parser.parse(new FileReader(jsonFileToLoad));
            LOGGER.debug("JSON loaded from file (original): {}", json.toJSONString());

            final ObjectMapper mapper = new ObjectMapper();
            final Map<String, Object> orderedMap = mapper.readValue(
                    json.toJSONString(), new TypeReference<Map<String, Object>>(){});

            LOGGER.debug("JSON from LinkedHashMap: {}", new ObjectMapper().writeValueAsString(orderedMap));

            final ObjectMapper mapperTreeMap = new ObjectMapper();
            final SimpleModule module = new SimpleModule();
            module.addAbstractTypeMapping(Map.class, TreeMap.class);
            mapperTreeMap.registerModule(module);

            final Map<String, Object> sortedMap = mapperTreeMap.readValue(
                    json.toJSONString(), new TypeReference<Map<String, Object>>(){});
            LOGGER.debug("JSON from TreeMap: {}", mapperTreeMap.writeValueAsString(sortedMap));

        } catch (FileNotFoundException e) {
            LOGGER.debug("File was not found: -{}-", jsonFileToLoad);
        } catch (IOException | ParseException e) {
            LOGGER.debug("Exception while parsing or handling file: -{}-", jsonFileToLoad);
            e.printStackTrace();
        }
    }

}