Convert Json to Map and Map to Json

Convert.java

package global.visto.tasks.util;

import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.stereotype.Service;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * Classe responsavel por fazer a conversao de HashMap para Json e vice-versa
 */
@Service
public class Convert {

    /**
     * Convert a Map into JSON string.
     *
     * @param map map de atributos
     * @return json String
     */
    public String mapToJson(Map<String, String> map) throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        String json = mapper.writeValueAsString(map);
        return json;
    }

    /**
     * Convert a Json to map
     *
     * @param json string json
     * @return Map de atributos
     */
    public Map<String, String> jsonToMap(String json) throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        Map map = mapper.readValue(json, Map.class);
        return map;
    }


    public static void main(String[] args) throws IOException {

        Convert convert = new Convert();

        Map personMap = new HashMap<>();
        Map personDetail = new HashMap();
        personDetail.put("firstname", "Felipe");
        personDetail.put("lastname", "Lima");
        personDetail.put("age", "32");
        personDetail.put("city", "Sao Paulo");
        personMap.put("person", personDetail);
        final String json = convert.mapToJson(personMap);
        System.out.println("json = " + json);

        final Map<String, String> map = convert.jsonToMap(json);
        System.out.println("Map is " + map);

        // convert json to Map
        String json2 = "{\"person\":{\"age\":\"32\",\"lastname\":\"Lima\""
                + ",\"firstname\":\"Felipe\",\"city\":\"SaoPaulo\"}}";

        String json3 = "{\"processVariablesValueEquals\":{[\"fixedvarJobId\":\"501\"]}\"}";

        final String s2 = "{\"processVariablesValueEquals\":[{\"fixedvarJobId\":\"501\"}]}";
        final String s3 = "{\"processVariablesValueEquals\":[{\"fixedvarJobId\":\"501\",\"name\":\"teste\"},{\"fixedvarJobId\":\"502\",\"name\":\"teste2\"}]}";

        System.out.println("Map2 is : " + convert.jsonToMap(s2));
        System.out.println("Map3 is : " + convert.jsonToMap(s3));
        System.out.println("JSON3 is : " + convert.mapToJson(convert.jsonToMap(s3)));

    }
}