Method invocation highlighed error in Android Studio

From what I've seen, Android Studio shows a bit too much warnings about potential NullPointerExceptions, even for methods that will never return null. I simply ignore some of them, but it's useful to carefully check all of them, because sometimes I missed an important one.

If you look at the android source code, it's easy to see that getFragmentManager() will never return null :

public FragmentManager getFragmentManager() {
    return mFragments;
}

Where mFragments is assigned only once through the whole class :

final FragmentManagerImpl mFragments = new FragmentManagerImpl();