NullPointerException : FragmentManager.beginTransaction()

FragmentManager will be null until it is attached to the activity.So use below code , If it is a nested Fragment use this.getChildFragmentManager() for your fragment class else use getActivity().getFragmentManager() or getActivity().getSupportFragmentManager().

Declare your FragmentTransaction and initialize it like this

FragmentTransaction fm;

@Override
public void onAttach(@NonNull Context context) {
    super.onAttach(context);
    fm = getFragmentManager();
}

Then on your code, you can call this

Fragment fragment = new PropertyFragment();
FragmentTransaction transaction = fm.beginTransaction();
transaction.add(R.id.rent_viewer, fragment).addToBackStack(null).commit();;