درخواست راهنمایی برای حل مشکل در آموزش شماره 16 بخش Ui Parser using Reflection

با سلام بنده طبق آموزش ها پیش رفتم ولی به مشکلی بر خوردم اونم این هست تصویر زیر :
مقداری پایین تر و در این قسمت کد کلاس قرار داده شده کلیک کنید.

 W: java.lang.IllegalAccessException: Class java.lang.Class<ir.vahidgarousi.app.framework.activity.UAppCompatActivity$Founder> cannot access 
 field android.widget.TextView ir.vahidgarousi.app.frameworkstartup.MainActivity$Ui.txtHello of class
 java.lang.Class<ir.vahidgarousi.app.frameworkstartup.MainActivity$Ui>
W:     at ir.vahidgarousi.app.framework.activity.UAppCompatActivity$Founder.build(UAppCompatActivity.java:118)

 UAppcompatActivity

package ir.vahidgarousi.app.framework.activity;

import android.app.ActionBar;
import android.app.Activity;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.support.annotation.LayoutRes;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Window;
import android.view.WindowManager;

import java.lang.reflect.Field;

import ir.vahidgarousi.app.framework.core.UBase;


public class UAppCompatActivity extends AppCompatActivity {

  @Override
  public void onCreate(@Nullable Bundle savedInstanceState, @Nullable PersistableBundle persistentState) {
    super.onCreate(savedInstanceState, persistentState);
  }

  @Override
  protected void onResume() {
    super.onResume();
    UBase.setCurrentActivity(this);
  }

  public static class Founder {

    private static final String TAG = "Founder";
    private final Activity activity;
    private int[] feauters;
    private boolean noTitleBar;
    private boolean noActionBar;
    private boolean fullScreen;
    private int layoutResId;
    private Object ui;

    public Founder(Activity activity) {
      this.activity = activity;
    }

    public Founder requestFeaturs(int... feauters) {
      this.feauters = feauters;

      return this;
    }

    public Founder noTitleBar() {
      noTitleBar = true;
      return this;
    }

    public Founder noActionBar() {
      noActionBar = true;
      return this;
    }

    public Founder fullScreen() {
      this.fullScreen = true;
      return this;
    }

    public Founder contentView(@LayoutRes int latoutResId) {
      this.layoutResId = latoutResId;
      return this;
    }

    public Founder extractUi(Object ui) {
      this.ui = ui;
      return this;
    }

    public Founder build() {
      for (int feature : this.feauters) {
        activity.getWindow().requestFeature(feature);
      }
      if (noTitleBar) {
        activity.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
      }

      if (fullScreen) {
        activity.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
      }
      if (noActionBar) {
        activity.getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
        {
          ActionBar actionBar = activity.getActionBar();
          if (actionBar != null) {
            actionBar.hide();
          }
        }
        if (activity instanceof AppCompatActivity) {
          AppCompatActivity castedActivity = (AppCompatActivity) activity;
          android.support.v7.app.ActionBar actionBar = castedActivity.getSupportActionBar();
          if (actionBar != null) {
            actionBar.hide();
          }
        }
      }
      activity.setContentView(layoutResId);
      {
        Class clazz = ui.getClass();
        Field[] fields = clazz.getDeclaredFields();
        for (Field field : fields) {
          String name = field.getName();
          Class type = field.getType();
          if (name.contains("$")) {
            continue;
          }
          Log.i(TAG, "name is : " + name + " type : " + type);
          int id = UBase.get().getResources().getIdentifier(name, "id", UBase.get().getPackageName());
          try {
            field.set(ui, activity.findViewById(id));
          } catch (IllegalAccessException e) {
            Log.i(TAG, "error");
            e.printStackTrace();
          }
        }
      }
      return this;
    }
  }
}