onSaveInstanceState doesn't work

I think you've fallen into a really common trap many devs have since the Android OS team overloaded the onSaveInstanceState() method.

You are overriding the wrong method. The one you want is:

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    String a = "WTF";
    outState.putString("hello",a);
}

Personally, I think Craig Mautner should be forced to donate money every time an Android developer makes this mistake - source