Android Activity onDestroy() is not always called and if called only part of the code is executed

onDestroy() is not always called. If called, only part of the code is executed. And most of the time in LogCat I only see the message "gps state on destroy called first". Why is that?

protected void onDestroy() {
    super.onDestroy();
    Log.d("on destroy called", "gps state on destroy called first");

    editor.putBoolean("gpsOn", false);
    Log.d("on destroy called", "gps state on destroy called second");
    editor.commit();

    Log.d("on destroy called", "gps state on destroy called third");
    stopRouteTracking();
    Log.d("on destroy called", "gps state on destroy called  fourth");
}

Take a look at this:

Activity OnDestroy never called?

And this:

http://developer.android.com/reference/android/app/Activity.html#onDestroy%28%29

Basically, there's never a guarantee that onDestroy() will be called, and in some cases processes such as your app will be killed directly, bypassing the method call anyway.