Whats wrong on ut Shared Preferences on a Null Object Reference?

I have a MainActivity and class with Shared Preferences.

public class MainActivity extends AppCompatActivity {


private SectionsPagerAdapter mSectionsPagerAdapter;


private ViewPager mViewPager;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

   if (DataStorage.getConfig(AppCore.getContext(),Const.FIRST).equals("true")){
        FragmentManager manager = getSupportFragmentManager();
        FirstDialog firstDialog = new FirstDialog();
        firstDialog.show(manager,"dialog");
        DataStorage.setConfig(AppCore.getActivity(), Const.FIRST,"false");
    }

}

And a DataStorage class with Shared Preferences:

public class DataStorage {

public static String getConfig(Context context, String name) {
    return getConfig(context, name, "");
}

public static String getConfig(Context context, String name, String defValue) {
    SharedPreferences settings = context.getSharedPreferences(
            Const.NAME, 0);
    String ret = settings.getString(name, defValue);
    return ret;
}

public static void setConfig(Context context, String name, String value) {
    SharedPreferences settings = context.getSharedPreferences(
            Const.NAME, 0);
    SharedPreferences.Editor editor = settings.edit();
    editor.putString(name, value);
    editor.commit();
}

}

So I have an error that say smth like this:

E/AndroidRuntime: FATAL EXCEPTION: main Process: nortti.ru.dogshelter, PID: 16246 java.lang.RuntimeException: Unable to start activity ComponentInfo{nortti.ru.dogshelter/nortti.ru.dogshelter.activities.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.SharedPreferences android.content.Context.getSharedPreferences(java.lang.String, int)' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2326) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) at android.app.ActivityThread.access$800(ActivityThread.java:147) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1281) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5264) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:900) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:695) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.SharedPreferences android.content.Context.getSharedPreferences(java.lang.String, int)' on a null object reference at nortti.ru.dogshelter.DataStorage.getConfig(DataStorage.java:15) at nortti.ru.dogshelter.DataStorage.getConfig(DataStorage.java:11) at nortti.ru.dogshelter.activities.MainActivity.onCreate(MainActivity.java:44) at android.app.Activity.performCreate(Activity.java:5975) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2269) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)  at android.app.ActivityThread.access$800(ActivityThread.java:147)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1281)  at android.os.Handler.dispatchMessage(Handler.java:102)  at android.os.Looper.loop(Looper.java:135)  at android.app.ActivityThread.main(ActivityThread.java:5264)  at java.lang.reflect.Method.invoke(Native Method)  at java.lang.reflect.Method.invoke(Method.java:372)  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:900)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:695) 

It's seamed that is womething wrong with a context in DataStorage.