gistfile1.txt

son gson = new GsonBuilder().serializeNulls().create();
 
        HttpLoggingInterceptor loggingInterceptor = new HttpLoggingInterceptor();
        loggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
 
        OkHttpClient okHttpClient = new OkHttpClient.Builder()
                .addInterceptor(new Interceptor() {
                    @Override
                    public okhttp3.Response intercept(Chain chain) throws IOException {
                        Request originalRequest = chain.request();
 
                        Request newRequest = originalRequest.newBuilder()
                                .header("Interceptor-Header", "xyz")
                                .build();
 
                        return chain.proceed(newRequest);
                    }
                })
                .addInterceptor(loggingInterceptor)
                .build();
 
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("https://jsonplaceholder.typicode.com/")
                .addConverterFactory(GsonConverterFactory.create())
                .client(okHttpClient)
                .build();
 
        jsonPlaceHolderApi = retrofit.create(JsonPlaceHolderApi.class);