Не могу разобраться с Holder и permission

public class CameraActivity extends AppCompatActivity implements SurfaceHolder.Callback, Camera.AutoFocusCallback, Camera.PictureCallback
{
    final int REQUEST_CODE_PERMISSION_READ_CONTACTS = 1;
    protected SurfaceHolder holder;
    protected SurfaceView surfaceView;
 
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
 
        setContentView(R.layout.activity_camera);
 
        surfaceView = findViewById(R.id.surfaceView);
        holder = surfaceView.getHolder();
 
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
        {
            ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.CAMERA},
                    REQUEST_CODE_PERMISSION_READ_CONTACTS);
        }
        else
        {
            start();
        }
    }
 
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
    {
        switch (requestCode)
        {
            case REQUEST_CODE_PERMISSION_READ_CONTACTS:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                {
                    start();
                }
                else
                {
                    Toast.makeText(this, R.string.not_premission, Toast.LENGTH_LONG).show();
                }
        }
    }
 
    private void start()
    {
        Toast.makeText(this, "START", Toast.LENGTH_LONG).show();
        holder.addCallback(this);
    }
 
    @Override
    public void surfaceCreated(SurfaceHolder surfaceHolder) {
        Log.d("my_c", "create");
    }
 
    @Override
    public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {
        Log.d("my_c", "change");
    }
 
    @Override
    public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
        Log.d("my_c", "delete");
    }
}