Empty fragments after reboot Activity

I am writing an Android application for Api 10-23 using Appcompat. In MainActivity there is a ViewPager on 3 tab fragments. Code like this:

 public class MainActivity extends AppCompatActivity { private TabLayout tabLayout; private TabsFragmentAdapter tabsFragmentAdapter; private void initToolbar() { Toolbar toolbar=(Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); toolbar.setTitle("Looker"); } private void initTabs() { ViewPager viewPager=(ViewPager) findViewById(R.id.viewPager); tabsFragmentAdapter= new TabsFragmentAdapter(getSupportFragmentManager() ); viewPager.setAdapter(tabsFragmentAdapter); tabLayout= (TabLayout)findViewById(R.id.tabLayout); tabLayout.setupWithViewPager(viewPager); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main_layout); DbHelper dbHelper= new DbHelper(this); dbHelper.initDb(); DbHelper.initCursors(); initToolbar(); initTabs(); } } public class TabsFragmentAdapter extends FragmentPagerAdapter { private HashMap<Integer,MainListFragment> tabs; public TabsFragmentAdapter(FragmentManager fm) { super(fm); initTabsMap(); } @Override public CharSequence getPageTitle(int position) { return tabs.get(position).getTitle(); } @Override public Fragment getItem(int position) { return tabs.get(position); } @Override public int getCount() { return tabs.size(); } private void initTabsMap() { tabs = new HashMap<>(); MainListFragment fragmentFilms= new Fragment_Films(); MainListFragment fragmentSerial= new Fragment_Serial(); MainListFragment fragmentMult= new Fragment_Serial(); fragmentFilms.initFragment("Фильмы",O.interaction.CONTENT_FILMS, R.layout.main_list_element_film); fragmentSerial.initFragment("Сериалы",O.interaction.CONTENT_SERIAL, R.layout.main_list_element_serial); fragmentMult.initFragment("Мульт-сериалы",O.interaction.CONTENT_MULT, R.layout.main_list_element_serial); tabs.put(O.interaction.CONTENT_FILMS, fragmentFilms); tabs.put(O.interaction.CONTENT_SERIAL, fragmentSerial); tabs.put(O.interaction.CONTENT_MULT, fragmentMult); } } public abstract class MainListFragment extends Fragment implements AdapterInterface { private String title; public int contentType; protected int listElementLayout; public void initFragment(String _title,int _contentType,int _listElementLayout) { title=_title; contentType=_contentType; listElementLayout=_listElementLayout; } public void initAdapter() { ... } @Nullable @Override public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) { super.onCreateView(inflater,container,savedInstanceState); View view= inflater.inflate(R.layout.main_list_fragment,container, false); return view; } } 

A lot of code, like content fragments, behind the scenes, of course. The main thing is that their initialization occurs from the base, where contentType points to a table, to the desired cursor.

Actually, the problem is:

When, for example, a screen rotation takes place, or maybe I went ahead for a couple of activities, and then did a taskKill , the MainActivity reloads and fragments are re-created. After that, the application crashes from cursor errors that look in the wrong tables. I was looking for a bug: changed the constants for contentType to 4,5,6 and found out that during a normal start the following sequence is executed:

 onCreate: main initTabsMap: TabsFragmentAdapter initFragment: 4 initFragment: 5 initFragment: 6 getItem: 4 getItem: 5 onCreateView: 4 initAdapter: 4 onCreateView: 5 initAdapter: 5 

When rebooting:

 onCreate: main initTabsMap: TabsFragmentAdapter initFragment: 4 initFragment: 5 initFragment: 6 onCreateView: 0 onCreateView: 0 initAdapter: 0 initAdapter: 0 

In the sense, fragments are created, initialized, but getItem not called and someone (maybe Fragment Manager, I do not know) gives me empty fragments. Tell me why this happens and what to do about it?