lifecycle/extensions/src/main/java/androidx/lifecycle/ViewModelProviders.java
@NonNull
    @MainThread
    public static ViewModelProvider of(@NonNull FragmentActivity activity) {
        return of(activity, null);
    }
/**
     * Creates a {@link ViewModelProvider}, which retains ViewModels while a scope of given Activity
     * is alive. More detailed explanation is in {@link ViewModel}.
     * <p>
     * It uses {@link ViewModelProvider.AndroidViewModelFactory} to instantiate new ViewModels.
     *
     * @param activity an activity, in whose scope ViewModels should be retained
     * @return a ViewModelProvider instance
     */
Creates a  ViewModelProvider, which retains ViewModels while a scope of given Activity
is alive. More detailed explanation is in  ViewModel.

@param activity an activity, in whose scope ViewModels should be retained
@return a ViewModelProvider instance
Creates a ViewModelProvider which retains ViewModels while a scope of given Activity is alive . More detailed explanation is in ViewModel . @param activity an activity in whose scope ViewModels should be retained @return a ViewModelProvider instance
@NonNull
    @MainThread
    public static ViewModelProvider of(@NonNull FragmentActivity activity) {
        return of(activity, null);
    }
@ NonNull @ MainThread public static ViewModelProvider of ( @ NonNull FragmentActivity activity ) { return of ( activity , null ) ; }
Creates a {@link ViewModelProvider}, which retains ViewModels while a scope of given Activity
 is alive.
Creates a { @link ViewModelProvider } which retains ViewModels while a scope of given Activity is alive .