Deserialization throws IllegalAccessException

Question

I'm trying to deserialize an object but it doesn't work.

Has anyone an idea how to handle it?

public static List<Leistung> findAll(Context ctx) {

    List<Leistung> result = null;
    FileInputStream in = null;
    Object obj = null;
    File f = ctx.getFileStreamPath("file.obj");
    if (f.exists()) {
        try {
            in = ctx.openFileInput("file.obj");
            ObjectInputStream objIn = new ObjectInputStream(in);
            // obj = objIn.readObject();
            obj = (ArrayList<Leistung>) objIn.readObject();
        } catch (Exception e) {
            Log.v(TAG, "read Failed");
            e.printStackTrace();
        } finally {
            try {
                in.close();
            } catch (IOException e) {
                Log.v(TAG, "close failed");
                e.printStackTrace();
            }
        }
    }
    if (obj != null) {
        result = (List<Leistung>) obj;
    } else {
        result = new ArrayList<Leistung>();
    }
    return result;
}

public static void persistAll(Context ctx, List<Leistung> leistungen) {

    FileOutputStream out = null;
    try {
        out = ctx.openFileOutput("file.obj", Context.MODE_PRIVATE);
        ObjectOutputStream objOut = new ObjectOutputStream(out);
        objOut.writeObject(leistungen);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

10-17 12:02:10.911: WARN/System.err(16429): java.io.InvalidClassException: de.moelders.notensammlerapp.Modul; IllegalAccessException 10-17 12:02:10.921: WARN/System.err(16429): at java.io.ObjectInputStream.resolveConstructorClass(ObjectInputStream.java:2010) 10-17 12:02:10.921: WARN/System.err(16429): at java.io.ObjectInputStream.readNewObject(ObjectInputStream.java:2095) 10-17 12:02:10.931: WARN/System.err(16429): at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:929) 10-17 12:02:10.941: WARN/System.err(16429): at java.io.ObjectInputStream.readObject(ObjectInputStream.java:2285) 10-17 12:02:10.941: WARN/System.err(16429): at java.io.ObjectInputStream.readObject(ObjectInputStream.java:2240) 10-17 12:02:10.941: WARN/System.err(16429): at java.util.ArrayList.readObject(ArrayList.java:662) 10-17 12:02:10.951: WARN/System.err(16429): at java.lang.reflect.Method.invokeNative(Native Method) 10-17 12:02:10.951: WARN/System.err(16429): at java.lang.reflect.Method.invoke(Method.java:521) 10-17 12:02:10.961: WARN/System.err(16429): at java.io.ObjectInputStream.readObjectForClass(ObjectInputStream.java:1537) 10-17 12:02:10.971: WARN/System.err(16429): at java.io.ObjectInputStream.readHierarchy(ObjectInputStream.java:1460) 10-17 12:02:10.971: WARN/System.err(16429): at java.io.ObjectInputStream.readNewObject(ObjectInputStream.java:2139) 10-17 12:02:10.981: WARN/System.err(16429): at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:929) 10-17 12:02:10.981: WARN/System.err(16429): at java.io.ObjectInputStream.readObject(ObjectInputStream.java:2285) 10-17 12:02:10.991: WARN/System.err(16429): at java.io.ObjectInputStream.readObject(ObjectInputStream.java:2240) 10-17 12:02:10.991: WARN/System.err(16429): at de.moelders.notensammlerapp.Storage.findAll(Storage.java:33) 10-17 12:02:11.001: WARN/System.err(16429): at de.moelders.notensammlerapp.NoteListe.onStart(NoteListe.java:21)