There are different open source libraries, which you can use for parsing json.
org.json :- If you want to read or write json then you can use this library.
First create JsonObject :-
JSONObject jsonObj = new JSONObject();
Now, use this object to get your values :-
String id = jsonObj.getString("id");
You can see complete example here
Jackson databind :- If you want to bind and parse your json to particular POJO class, then you can use jackson-databind library, this will bind your json to POJO class :-
ObjectMapper mapper = new ObjectMapper();
post= mapper.readValue(json, Post.class);
You can see complete example here