remove element from set java/android

Remove all elements from set:
Set<Integer> set = new HashSet<Integer>();

set.add(1);
set.add(2);
set.add(3);
set.add(4);

Iterator<Integer> itr = set.iterator();  // list is a Set<Integer>!
        while (itr.hasNext())
        {
            Integer s = itr.next();
                itr.remove();

        }

Android: java.lang.IllegalStateException: This YouTubePlayer has been released

Process: com.daily.buzz, PID: 27644
    java.lang.IllegalStateException: This YouTubePlayer has been released
        at lmi.a(SourceFile:104)
        at lmi.a(SourceFile:181)
        at amrc.dispatchTransaction(SourceFile:162)
        at dbb.onTransact(SourceFile:7)
        at android.os.Binder.transact(Binder.java:387)
        at com.google.android.youtube.player.internal.d$a$a.a(Unknown Source)
        at com.google.android.youtube.player.internal.s.cueVideo(Unknown Source)
        at com.google.android.youtube.player.internal.s.cueVideo(Unknown Source)
        at com.daily.buzz.Search.SearchResultActivity.onClickedVideo(SearchResultActivity.java:170)
        at com.daily.buzz.Search.SearchTabItemsFragment.onVideoItemViewClick(SearchTabItemsFragment.java:215)
        at com.daily.buzz.Search.SearchResultRecyclerViewAdapter$1.onClick(SearchResultRecyclerViewAdapter.java:153)
        at android.view.View.performClick(View.java:5215)
        at android.view.View$PerformClick.run(View.java:21196)
        at android.os.Handler.handleCallback(Handler.java:742)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:157)
        at android.app.ActivityThread.main(ActivityThread.java:5603)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:774)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:652)

Fatal Exception: java.lang.IllegalStateException: Failure saving state: active fragment was removed from the FragmentManager

ANDROID STUDIO ERROR LOG:

E/FragmentManager: Failure saving state: active AllStoresFragmentListV2{fd50037 (4a8b618e-a0a8-45d0-aa37-ba08393b8f68) id=0x7f08009c} was removed from the FragmentManager
01-09 11:34:42.768 19169-19169/com.android.app E/FragmentManager: Activity state:
01-09 11:34:42.805 4746-6075/? E/ExecutionCriteria: Package unavailable for task: com.google.android.apps.fitness/.api.services.summary.ActivitySummaryGcmTaskService{u=0 tag="ActivitySummaryGcmTaskService" trigger=window{period=1800s,flex=180s,earliest=-27143018s,latest=-27142838s} requirements=[NET_ANY] attributes=[PERSISTED,RECURRING] scheduled=-27144638s last_run=N/A jid=N/A status=PENDING retries=0 client_lib=MANCHEGO_GCM-10400000}
01-09 11:34:42.880 19169-19169/com.android.app E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.android.app, PID: 19169
    java.lang.IllegalStateException: Failure saving state: active AllStoresFragmentListV2{fd50037 (4a8b618e-a0a8-45d0-aa37-ba08393b8f68) id=0x7f08009c} was removed from the FragmentManager
        at androidx.fragment.app.FragmentManagerImpl.saveAllState(FragmentManagerImpl.java:2315)
        at androidx.fragment.app.FragmentController.saveAllState(FragmentController.java:150)
        at androidx.fragment.app.FragmentActivity.onSaveInstanceState(FragmentActivity.java:496)
        at androidx.appcompat.app.AppCompatActivity.onSaveInstanceState(AppCompatActivity.java:511)
        at android.app.Activity.performSaveInstanceState(Activity.java:1348)
        at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1290)
        at android.app.ActivityThread.callCallActivityOnSaveInstanceState(ActivityThread.java:4202)
        at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3592)
        at android.app.ActivityThread.handleStopActivity(ActivityThread.java:3658)
        at android.app.ActivityThread.access$1400(ActivityThread.java:151)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1429)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:157)
        at android.app.ActivityThread.main(ActivityThread.java:5603)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:774)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:652)

Here, App using the latest gradle as below implementation 'androidx.core:core:1.1.0-alpha03'
I have compared crashing fragment with other fragment code and found the difference as below: Crashing fragment has method setRetainInstance(true); inside onCreateView() as shown in below snippet.

@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 setRetainInstance(true);
}

I come across the link which says not to use setRetainInstance : setRetainInstance - This can only be used with fragments not in the back stack I removed the setRetainInstance(true) for crashing fragmnet; It's working now.

HOW TO REPLICATE THIS ISSUE:
MainActivity --> HomeFragment --> FirstFragment(crashing fragment) --> HomeFragment
MainActivity loads with HomeFragment which replaced by FirstFragment and then going back to HomeFragment. Then moving my app to background and crash happens with below exception.

 java.lang.IllegalStateException: Failure saving state: active FirstFragment{fd50037 (4a8b618e-a0a8-45d0-aa37-ba08393b8f68) id=0x7f08009c} was removed from the FragmentManager

Read More about setRetainInstance(true)