How to bind configuration objects from appsettings.json to user objects correctly

I started some basic project on .net Core 1.1, and I wish to map some properties from appsettings.json to object, but I probably can't understand correct name convention or something pretty basic

Regarding MSDN Using Options and configuration objects section, it is very easy to use it. I added next lines to appsettings.json

{
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Warning"
    }
  },

  "XXXOptions": {
    "X1": {
      "AppId": "11",
      "AppCode": "22"
    },
    "X2": {
      "AppId": "",
      "AppCode": ""
    }
  }
}

I added custom class

 public class XXXOptions
    {
        public XXXOptions()
        {
        }
        public X1 X1{ get; set; }
        public X2 X2{ get; set; }
    }

    public class X1
    {
        public int AppId { get; set; }
        public int AppCode { get; set; }
    }

    public class X2
    {
        public int AppId { get; set; }
        public int AppCode { get; set; }
    }

I added next code to Startup.cs

  public void ConfigureServices(IServiceCollection services)
        {
            // Adds services required for using options.
            services.AddOptions();

            // Register the IConfiguration instance which MyOptions binds against.
            services.Configure<XXXOptions>(Configuration);

            // Add framework services.
            services.AddMvc();
        }

 public class XXXController : Controller
    {
        private readonly XXXOptions _options;
        public XXXController(IOptions<XXXOptions> optionsAccessor)
        {
            _options = optionsAccessor.Value;
        }

        public IActionResult Index()
        {
            var option1 = _options.X1;
            return Content($"option1 = {option1.AppCode}, option2 = {option1.AppId}");
            return View();
        }
    }

optionsAccessor.Value - Value containes null values at XXXController constructor.

but it seems like framework show mappet values at JsonConfigurationProvider inside of Configuration property

any ideas?