在Android上从bundle中检索数据时出现ClassCastException

我有一些状态,我希望在片段的生命周期中保存.例如,当屏幕旋转时,它工作正常,但是当从磁盘中杀死并恢复进程时(我认为它是如何工作的),我得到一个ClassCastException.
这是一些代码：

初始化：

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState == null) {
        playlistsMap = new LinkedHashMap<Section,List<Playlist>>();
    } else {
        playlistsMap = (LinkedHashMap<Section,List<Playlist>>) savedInstanceState.getSerializable(PLAYLISTS_MAP_KEY);
    }
    setHasOptionsMenu(true);
}

保存数据：

@Override
public void onSaveInstanceState(Bundle outState) {
    if (isEverySectionsLoaded()) {
        outState.putSerializable(PLAYLISTS_MAP_KEY,playlistsMap);
    } else {
        outState.putSerializable(PLAYLISTS_MAP_KEY,new LinkedHashMap<Section,List<Playlist>>());
    }
    // ...
}

我从onCreate中的强制转换得到的例外：

04-10 01:06:43.430 E/AndroidRuntime(28549): FATAL EXCEPTION: main
04-10 01:06:43.430 E/AndroidRuntime(28549): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mydomain.android/com.mydomain.android.ui.MainActivity}: 
java.lang.classCastException: java.util.HashMap cannot be cast to java.util.LinkedHashMap

我知道在Android上使用parcelables会更好,但我仍然不明白这是怎么回事.

有任何想法吗？

private LinkedHashMap<Section,List<Playlist>> playlistsMap;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState == null) {
        playlistsMap = new LinkedHashMap<Section,List<Playlist>>();
    } else {
        //assuming the bug returns a hashmap
        Map<Section,List<Playlist>> items = (Map<Section,List<Playlist>>) savedInstanceState.getSerializable(PLAYLISTS_MAP_KEY);

        //this way you can ensure you are working with a linkedHashMap. 
        //for the rest off the application
        playlistsMap.putAll(items);
    }
    setHasOptionsMenu(true);
}