IssueTracker

what Application are you trying to reproduce the issue. I tried rotating the device for couple of times, Issue not seen. Also provide Device you are using to reproduce the issue

Any Android 2.3.x, really. The application is a Beta version of an unreleased app.

This issie initially appeared on a Samsung Galaxy Ace with 2.3.3, but after testing it in an Android emulator, it also appeared. The dificulty to reproduce this is because it only seems to happen after a crash of the app (either by OOM or some other bug), and we Android tries to recreate the app, it crashes again with the "ClassNotFoundException when unmarshalling".

Also, we're having another crash similar to this, but in AppBarLayout.Behaviour:

Fatal Exception: java.lang.RuntimeException: Unable to start activity ComponentInfo{cm.aptoide.pt.dev/cm.aptoide.pt.AppViewActivity}: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.design.widget.AppBarLayout$Behavior$SavedState
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1658)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1674)
       at android.app.ActivityThread.access$1500(ActivityThread.java:117)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:942)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:130)
       at android.app.ActivityThread.main(ActivityThread.java:3735)
       at java.lang.reflect.Method.invokeNative(Method.java)
       at java.lang.reflect.Method.invoke(Method.java:507)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:662)
       at dalvik.system.NativeStart.main(NativeStart.java)
Caused by android.os.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.design.widget.AppBarLayout$Behavior$SavedState
       at android.os.Parcel.readParcelable(Parcel.java:1958)
       at android.os.Parcel.readParcelableArray(Parcel.java:1997)
       at android.support.design.widget.CoordinatorLayout$SavedState.<init>(CoordinatorLayout.java:2604)
       at android.support.design.widget.CoordinatorLayout$SavedState$1.createFromParcel(CoordinatorLayout.java:2639)
       at android.support.design.widget.CoordinatorLayout$SavedState$1.createFromParcel(CoordinatorLayout.java:2636)
       at android.support.v4.os.ParcelableCompat$CompatCreator.createFromParcel(ParcelableCompat.java:51)
       at android.os.Parcel.readParcelable(Parcel.java:1981)
       at android.os.Parcel.readValue(Parcel.java:1846)
       at android.os.Parcel.readSparseArrayInternal(Parcel.java:2112)
       at android.os.Parcel.readSparseArray(Parcel.java:1568)
       at android.os.Parcel.readValue(Parcel.java:1903)
       at android.os.Parcel.readMapInternal(Parcel.java:2083)
       at android.os.Bundle.unparcel(Bundle.java:208)
       at android.os.Bundle.getSparseParcelableArray(Bundle.java:1175)
       at com.android.internal.policy.impl.PhoneWindow.restoreHierarchyState(PhoneWindow.java:1517)
       at android.app.Activity.onRestoreInstanceState(Activity.java:844)
       at android.app.Activity.performRestoreInstanceState(Activity.java:816)
       at android.app.Instrumentation.callActivityOnRestoreInstanceState(Instrumentation.java:1096)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1636)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1674)
       at android.app.ActivityThread.access$1500(ActivityThread.java:117)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:942)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:130)
       at android.app.ActivityThread.main(ActivityThread.java:3735)
       at java.lang.reflect.Method.invokeNative(Method.java)
       at java.lang.reflect.Method.invoke(Method.java:507)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:662)
       at dalvik.system.NativeStart.main(NativeStart.java)

Thanks in advance.

Hi Please provide the sample project to reproduce the issue, Also our eng teams are not prioritizing changes on earlier releases.

It does the very same with VLC on Android:
git://code.videolan.org/videolan/vlc-android.git

Android 2.3.3 - 2.3.7
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.rusdelphi.wifipassword/com.rusdelphi.wifipassword.MainActivity}: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.design.widget.AppBarLayout$Behavior$SavedState
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1735)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1754)
        at android.app.ActivityThread.access$1500(ActivityThread.java:156)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1000)
        at android.os.Handler.dispatchMessage(Handler.java:130)
        at android.os.Looper.loop(SourceFile:351)
        at android.app.ActivityThread.main(ActivityThread.java:3821)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:538)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:969)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:727)
        at dalvik.system.NativeStart.main(Native Method)
Caused by: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.design.widget.AppBarLayout$Behavior$SavedState
        at android.os.Parcel.readParcelable(Parcel.java:1989)
        at android.os.Parcel.readParcelableArray(Parcel.java:2028)
        at android.support.design.widget.CoordinatorLayout$SavedState.<init>(Unknown Source)
        at android.support.design.widget.CoordinatorLayout$SavedState$1.createFromParcel(Unknown Source)
        at android.support.design.widget.CoordinatorLayout$SavedState$1.createFromParcel(Unknown Source)
        at android.support.v4.e.d.createFromParcel(Unknown Source)
        at android.os.Parcel.readParcelable(Parcel.java:2012)
        at android.os.Parcel.readValue(Parcel.java:1877)
        at android.os.Parcel.readSparseArrayInternal(Parcel.java:2143)
        at android.os.Parcel.readSparseArray(Parcel.java:1599)
        at android.os.Parcel.readValue(Parcel.java:1934)
        at android.os.Parcel.readMapInternal(Parcel.java:2114)
        at android.os.Bundle.unparcel(Bundle.java:239)
        at android.os.Bundle.getSparseParcelableArray(Bundle.java:1198)
        at com.android.internal.policy.impl.PhoneWindow.restoreHierarchyState(PhoneWindow.java:1538)
        at android.app.Activity.onRestoreInstanceState(Activity.java:880)
        at android.app.Activity.performRestoreInstanceState(Activity.java:852)
        at android.app.Instrumentation.callActivityOnRestoreInstanceState(Instrumentation.java:1132)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1713)
        ... 11 more

Layout
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <RelativeLayout
        android:id="@+id/MainView"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                android:theme="@style/ThemeOverlay.AppCompat.Dark" />

            <LinearLayout
                android:id="@+id/ad_view"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_gravity="center|bottom"
                android:orientation="vertical" />

            <android.support.design.widget.TabLayout
                android:id="@+id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="?attr/colorPrimary"
                android:theme="@style/ThemeOverlay.AppCompat.Dark"
                app:tabGravity="fill" />

            <android.support.v4.view.ViewPager
                android:id="@+id/viewpager"
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="1" />

        </LinearLayout>

        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_alignParentRight="true"
            android:layout_margin="@dimen/fab_margin"
            android:layout_marginBottom="@dimen/activity_vertical_margin"
            android:layout_marginRight="@dimen/activity_horizontal_margin"
            android:onClick="onAddButtonClick"
            android:src="@drawable/ic_add_black_24dp"
            android:visibility="invisible"
            app:layout_behavior="com.rusdelphi.wifipassword.FABScrollBehavior" />


    </RelativeLayout>

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:menu="@menu/drawer_view" />
</android.support.v4.widget.DrawerLayout>

This is our #1 crash in crashlytics.  Same behavior and types of crashes.

Happens on HoneyComb too.

Another stacktrace, in case it could bring some more info:

java.lang.RuntimeException: Unable to start activity ComponentInfo{org.videolan.vlc/org.videolan.vlc.gui.MainActivity}: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.v7.widget.RecyclerView$SavedState
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1696)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1716)
        at android.app.ActivityThread.access$1500(ActivityThread.java:124)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:968)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:130)
        at android.app.ActivityThread.main(ActivityThread.java:3806)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:507)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
        at dalvik.system.NativeStart.main(Native Method)
        at Android.MODEL(MB855)
        at Android.VERSION(2.3.5)
        at Android.FINGERPRINT(sprint/moto_sunfire/sunfire:2.3.5/4.5.1A-1_SUN-254_13/CM:user/release-keys)
Caused by: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.v7.widget.RecyclerView$SavedState
        at android.os.Parcel.readParcelable(Parcel.java:1958)
        at android.os.Parcel.readValue(Parcel.java:1846)
        at android.os.Parcel.readSparseArrayInternal(Parcel.java:2112)
        at android.os.Parcel.readSparseArray(Parcel.java:1568)
        at android.os.Parcel.readValue(Parcel.java:1903)
        at android.os.Parcel.readMapInternal(Parcel.java:2083)
        at android.os.Bundle.unparcel(Bundle.java:208)
        at android.os.Bundle.getSparseParcelableArray(Bundle.java:1167)
        at android.support.design.internal.NavigationMenuPresenter.onRestoreInstanceState(NavigationMenuPresenter.java:175)
        at android.support.v7.view.menu.MenuBuilder.dispatchRestoreInstanceState(MenuBuilder.java:349)
        at android.support.v7.view.menu.MenuBuilder.restorePresenterStates(MenuBuilder.java:361)
        at android.support.design.widget.NavigationView.onRestoreInstanceState(NavigationView.java:191)
        at android.view.View.dispatchRestoreInstanceState(View.java:6278)
        at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:1211)
        at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:1215)
        at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:1215)
        at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:1215)
        at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:1215)
        at android.view.View.restoreHierarchyState(View.java:6257)
        at com.android.internal.policy.impl.PhoneWindow.restoreHierarchyState(PhoneWindow.java:1724)
        at android.app.Activity.onRestoreInstanceState(Activity.java:868)
        at android.app.Activity.performRestoreInstanceState(Activity.java:840)
        at android.app.Instrumentation.callActivityOnRestoreInstanceState(Instrumentation.java:1096)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1674)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1716)
        at android.app.ActivityThread.access$1500(ActivityThread.java:124)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:968)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:130)
        at android.app.ActivityThread.main(ActivityThread.java:3806)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:507)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
        at dalvik.system.NativeStart.main(Native Method)

This issue could not be reproduced in Marshmallow builds. At this point, our eng teams are not prioritizing changes on earlier releases. Please do let us know if you encounter this issue on 6.0+.

This makes me sad.  Because we still have about 10% of our user base that can be affected by this.  

Are you aware of any work arounds for this issue?

We considered explicitly setting the class loader during the saving of the state in hopes that might fix it.  But, we're not sure of any additional ramifications that might have on saving state.

And, it's not specific to just Android 2, though, this is mostly the case.

97% Android 2
1% Android 4
1% Android 3
1% Other

Any advice would be greatly appreciated.

Do you have a multi-dex setup? If so and RecyclerView is in the secondary dex, I guess this might happen.
The SavedState was not public on an earlier version of the library which could cause this issue but it is already fixed now (+ 23.1.1 should have it public).

Another thing to check might be the proguard setup to ensure that the SavedState class is not being stripped.

We're not currently using multidex and have these two lines in our proguard config:

-keep class android.support.design.widget.AppBarLayout$Behavior$SavedState { *; }
-keep class android.support.design.widget.CoordinatorLayout$SavedState { *; }

When looking through the mapping files, SavedState seems to be preserved.  But, I could be misreading it.