import java.io.IOException;

 import java.util.HashMap;

 import java.util.Map;

 import com.fasterxml.jackson.core.JsonParseException;

 import com.fasterxml.jackson.core.type.TypeReference;

 import com.fasterxml.jackson.databind.JsonMappingException;

 import com.fasterxml.jackson.databind.ObjectMapper;

 import com.fasterxml.jackson.databind.SerializationFeature;

 public class ObjectMapperDemo {

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

         ObjectMapper objectMapper = new ObjectMapper();

         //Set pretty printing of json

         objectMapper.enable(SerializationFeature.INDENT_OUTPUT);

         //Define map which will be converted to JSON

         Map<String, String>mapIdPerson  = new HashMap<String, String>();

         mapIdPerson.put("id", "001");

         mapIdPerson.put("name", "James");

         mapIdPerson.put("age", "13");

         mapIdPerson.put("address", "street \"18");

         //1. Convert Map to JSON

         String mapToJson = objectMapper.writeValueAsString(mapIdPerson);

         System.out.println("1. Convert Map to JSON :");

         System.out.println(mapToJson);

         //2. JSON to Map

         //Define Custom Type reference for map type

         TypeReference<Map<String, String>> mapType = new TypeReference<Map<String,String>>() {};

         Map<String,String> jsonToMap = objectMapper.readValue(mapToJson, mapType);

         System.out.println("\n2. Convert JSON to Map :");

         // Print map output using Java 8

         // lambda expressions

         jsonToMap.forEach((k, v) ->

                             System.out.println(k + "=" + v));

     }

 }

 1. Convert Map to JSON :

 {

   "address" : "street \"18",

   "name" : "James",

   "id" : "001",

   "age" : "13"

 }

 2. Convert JSON to Map :

 address=street "18

 name=James

 id=001

 age=13