Attempt to invoke virtual method 'void androidx.recyclerview.widget.RecyclerView.removeViewAt(int)' on a null object reference

Ошибка:

java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.recyclerview.widget.RecyclerView.removeViewAt(int)' on a null object reference
W/System.err:     at com.arvicapps.geomitric_wallpapers.FavoriteFullImageActivity$5.onFavoriteChanged(FavoriteFullImageActivity.java:533)
        at com.github.ivbaranov.mfb.MaterialFavoriteButton.updateFavoriteButton(MaterialFavoriteButton.java:324)
        at com.github.ivbaranov.mfb.MaterialFavoriteButton.setFavorite(MaterialFavoriteButton.java:257)
        at com.github.ivbaranov.mfb.MaterialFavoriteButton.toggleFavorite(MaterialFavoriteButton.java:292)
W/System.err:     at com.github.ivbaranov.mfb.MaterialFavoriteButton$1.onClick(MaterialFavoriteButton.java:152)
        at android.view.View.performClick(View.java:6659)
        at android.view.View.performClickInternal(View.java:6631)
        at android.view.View.access$3100(View.java:790)
        at android.view.View$PerformClick.run(View.java:26187)
        at android.os.Handler.handleCallback(Handler.java:907)

Вот части кода из FavouriteFullImageActivity.java: @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_favorite_full_image); getSupportActionBar().hide(); RecyclerView recyclerView = findViewById(R.id.FavoriteCategoryView); }

Вот части кода из FavouriteFullImageActivity.java:

@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_favorite_full_image); getSupportActionBar().hide(); RecyclerView recyclerView = findViewById(R.id.FavoriteCategoryView); 
}

try {
 recyclerView.removeViewAt(position); recyclerView.notifyAll(); 
myDbHelper.closeDb(); 
myDbHelper.close(); 
myDbHelper.notifyAll(); 
} catch (NullPointerException nullPointerException) { nullPointerException.printStackTrace();
 }

Как решить?