Does the StringBuffer change the order of JSON?

Question

I'm using StringBuffer to get JSON from a URL.

This is the original JSON

[{"name":"Italy","topLevelDomain":[".it"],"alpha2Code":"IT","alpha3Code":"ITA","callingCodes":["39"],"capital":"Rome","altSpellings":["IT","Italian Republic","Repubblica italiana"],"region":"Europe","subregion":"Southern Europe","population":60665551,"latlng":[42.83333333,12.83333333],"demonym":"Italian","area":301336.0,"gini":36.0,"timezones":["UTC+01:00"],"borders":["AUT","FRA","SMR","SVN","CHE","VAT"],"nativeName":"Italia","numericCode":"380","currencies":[{"code":"EUR","name":"Euro","symbol":"€"}],"languages":[{"iso639_1":"it","iso639_2":"ita","name":"Italian","nativeName":"Italiano"}],"translations":{"de":"Italien","es":"Italia","fr":"Italie","ja":"イタリア","it":"Italia","br":"Itália","pt":"Itália","nl":"Italië","hr":"Italija","fa":"ایتالیا"},"flag":"https://restcountries.eu/data/ita.svg","regionalBlocs":[{"acronym":"EU","name":"European Union","otherAcronyms":[],"otherNames":[]}],"cioc":"ITA"}]

This is the JSON That I end up with once I convert it to a string from the response

[{"area":301336,"nativeName":"Italia","capital":"Rome","demonym":"Italian","flag":"https://restcountries.eu/data/ita.svg","alpha2Code":"IT","languages":[{"nativeName":"Italiano","iso639_2":"ita","name":"Italian","iso639_1":"it"}],"borders":["AUT","FRA","SMR","SVN","CHE","VAT"],"subregion":"Southern Europe","callingCodes":["39"],"regionalBlocs":[{"otherNames":[],"acronym":"EU","name":"European Union","otherAcronyms":[]}],"gini":36,"population":60665551,"numericCode":"380","alpha3Code":"ITA","topLevelDomain":[".it"],"timezones":["UTC+01:00"],"cioc":"ITA","translations":{"br":"Itália","de":"Italien","pt":"Itália","ja":"イタリア","hr":"Italija","it":"Italia","fa":"ایتالیا","fr":"Italie","es":"Italia","nl":"Italië"},"name":"Italy","altSpellings":["IT","Italian Republic","Repubblica italiana"],"region":"Europe","latlng":[42.83333333,12.83333333],"currencies":[{"symbol":"\u20ac","code":"EUR","name":"Euro"}]}]

This is my code for getting the JSON + Converting it.

        JSONArray JSON = null;

        //Reading Variables
        BufferedReader r = new BufferedReader(new InputStreamReader(con.getInputStream()));
        String input;
        StringBuffer response = new StringBuffer();

        //Adding response to StringBuffer
        while((input = r.readLine()) != null) {
            response.append(input);
        }

        //Stopping the reader
        r.close();

        System.out.println(response);
        //Convert StringBuffer to JSON
        JSON = new JSONArray(response.toString());
        System.out.println(JSON);
        return JSON;

Is there a way of preventing it from doing this?

score 1 · Accepted Answer · answered Apr 27 '20 at 13:07

It's not the StringBuffer but the JSONArray.

The order of elements in an array [] is maintained like the list ["AUT","FRA","SMR","SVN","CHE","VAT"] in both examples.

Anything as a name value pair surrounded by {} can be reordered like {"code":"EUR","name":"Euro","symbol":"€"} and {"symbol":"\u20ac","code":"EUR","name":"Euro"}.

To prevent this, you can keep it as a String or create your own object and define the toString method.

Stephen C · Answer 2 · 2020-04-27T13:22:35.600

Your question is similar to Keep the order of the JSON keys during JSON conversion to CSV.

It is not StringBuffer doing this. It is the JSON implementation itself.

For a start, according to all of the JSON specifications that I have seen, the order of the attributes of a JSON object are not significant. A JSON parser is not expected to preserve the attribute order, and neither is the in memory representation of a JSON object. So, for example, a typical in-memory representation of a JSON object uses a HashMap to hold the attribute names and values.

So my first piece of advice to you would be to change your application so that the order of the JSON attributes doesn't matter. If you design a JSON API where attribute order matters, then your API will be problematic.

(If this is in a testcase, it is not difficult to compare JSON properly. For example, parse the JSON and compare objects attribute by attribute.)

If you are lumbered with a (so-called) JSON API where the order of attributes has some meaning, my advice is:

Complain. Submit a bug report. This is not a proper JSON API.
Look for a JSON library that provides a way to work around the bad design. For example, some libraries allow you to provide a Map class to be used when constructing a JSONObject. The default is usually HashMap, but you could use LinkedHashMap instead.

Does the StringBuffer change the order of JSON?

2 Answers2