public class JacksonJrConverters<T> extends Converter.Factory {

    private static final MediaType MEDIA_TYPE = MediaType.parse("application/json; charset=UTF-8");
    protected static final String PROTOCOL_CHARSET = "utf-8";

    private Class<T> clazz;

    public JacksonJrConverters(Class<T> tClass) {
        super();
        this.clazz = tClass;
    }


    @Override
    public Converter<ResponseBody, ?> fromResponseBody(Type type, Annotation[] annotations) {
        super.fromResponseBody(type, annotations);

        if (clazz.equals(type)) {

            return new Converter<ResponseBody, T>() {
                @Override
                public T convert(ResponseBody value) throws IOException {

                    return JSON.std.beanFrom(clazz, value.bytes());
                }
            };
        }

        return null;
    }

    @Override
    public Converter<?, RequestBody> toRequestBody(Type type, Annotation[] annotations) {
        super.toRequestBody(type, annotations);

        if (clazz.equals(type)) {
            return new Converter<T, RequestBody>() {
                @Override
                public RequestBody convert(T value) throws IOException {

                    String strs = JSON.std.asString(value);

                    return RequestBody.create(MEDIA_TYPE, strs.getBytes(PROTOCOL_CHARSET));
                }
            };
        }
        return null;
    }
}

public class RestClientsJackson<T> {

    //use class T as generic for Jackson Jr parsing reference
    private Class<T> mClass;
    private OkHttpClient mOkHttpClient;
    public static final String ALAMAT_SERVERS = "https://api.github.com";


    public RestClientsJackson(Class<T> aClass) {
        mClass = aClass;

        mOkHttpClient = new OkHttpClient();
        mOkHttpClient.setConnectTimeout(10, TimeUnit.SECONDS);
        mOkHttpClient.setWriteTimeout(15, TimeUnit.SECONDS);
        mOkHttpClient.setReadTimeout(20, TimeUnit.SECONDS);
    }

    //with jackson jr converter
    public Apis getApiServicesJackson() {

        Log.w("API NULL", "API NULL, INIT LAGI");

        Retrofit.Builder retrobuilder = new Retrofit.Builder();
        retrobuilder.baseUrl(ALAMAT_SERVERS);
        retrobuilder.client(mOkHttpClient);

        retrobuilder.addConverterFactory(new JacksonJrConverters<>(mClass));

        Retrofit retrofits = retrobuilder.build();

        return retrofits.create(Apis.class);
    }
}