user-mw

public сlass HolderFragment extends Fragment {

  // Other code
  
  private ViewModelStore mViewModelStore = new ViewModelStore();

  public HolderFragment() {
     setRetainInstance(true);
  }

user-mw

public abstract class ViewModel {
   /**
    Long comment
    */
   @SuppressWarnings("WeakerAccess")
   protected void onCleared() {
   }
}

user-mw

public class ViewModelProviders {

  public static ViewModelProvider of(// arguments) {
    // Code
    return new ViewModelProvider(ViewModelStores.of(fragment), factory);
  }

  public static ViewModelProvider of(// arguments) {
    // Code
    return new ViewModelProvider(ViewModelStores.of(activity), factory);

user-mw

public class ViewModelProvider {

  DEFAULT_KEY = "android.arch.lifecycle.ViewModelProvider.DefaultKey";
  
  // Code

  public <T extends ViewModel> T get(Class<T> modelClass) {
    String canonicalName = modelClass.getCanonicalName();
    // Code

user-mw

public <T extends ViewModel> T get(@NonNull String key, @NonNull Class<T> modelClass) {
    ViewModel viewModel = mViewModelStore.get(key);

    if (modelClass.isInstance(viewModel)) {
      return (T) viewModel;
    } else {
       // Сode
    }

    viewModel = mFactory.create(modelClass);

user-mw

public сlass ViewModelStores {

  public static ViewModelStore of(FragmentActivity activity) {
    if (activity instanceof ViewModelStoreOwner) {
      return ((ViewModelStoreOwner) activity).getViewModelStore();
    }
    return holderFragmentFor(activity).getViewModelStore();
  }

  // Code

user-mw

public сlass HolderFragment extends Fragment {

  // Code
  
  public static HolderFragment holderFragmentFor(FragmentActivity activity) {
    return sHolderFragmentManager.holderFragmentFor(activity);
  }

  public static HolderFragment holderFragmentFor(Fragment fragment) {
    return sHolderFragmentManager.holderFragmentFor(fragment);

user-mw

public class ViewModelProviders {

  public static ViewModelProvider of(// arguments) {
    // Code
    return new ViewModelProvider(fragment.getViewModelStore(), factory);
  }
  
  public static ViewModelProvider of(// arguments) {
    // Code
    return new ViewModelProvider(activity.getViewModelStore(), factory);

user-mw

public ViewModelStore getViewModelStore() {
   // Code   
   if (mViewModelStore == null) {
       NonConfigurationInstances nc =
          (NonConfigurationInstances) getLastNonConfigurationInstance();
       
	if (nc != null) {
           mViewModelStore = nc.viewModelStore;
       	}
       	if (mViewModelStore == null) {

user-mw

public class Activity extends ContextThemeWrapper
 implements LayoutInflater.Factory2,
        //Code {
        
    // Code

    public Object getLastNonConfigurationInstance() {
        return mLastNonConfigurationInstances != null
                ? mLastNonConfigurationInstances.activity : null;
    }