title: findFragmentById() and findFragmentByTag()
body: <p>I created a Fragment to display my recycler view. so I used the method <strong>findFragmentById()</strong> to find my xml file. The problem is each time  i rotated the screen, it created one more recycler view stacks on top of one another.
  here is my code:</p>
  
  <pre><code>@Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
  
      ListFragment savedFragment = (ListFragment) getSupportFragmentManager().findFragmentById(R.id.list_recyclerview);
  
      if(savedFragment == null)
      {
          ListFragment fragment  = new ListFragment();
          FragmentManager fragmentManager = getSupportFragmentManager();
          FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
          fragmentTransaction.add(R.id.place_holder,fragment);
          fragmentTransaction.commit();
  
      }
  }
  </code></pre>
  
  <p>But when I used the method  <strong>findFragmentByTag()</strong>, it didn't happened.</p>
  
  <p>May anyone explain to me what are the difference between those 2 methods?</p>