Question

ClassCastException occurs randomly to restore Vector in onRestoreInstanceState().
Generally restoring vector is finished well, but sometimes exception occurs.

I think it happens when activity is went to background and destroyed but I’m not sure.

Any ideas? Thank you.

Stack<LocationInfo> mLocationInfoVector;

@Override
protected void onSaveInstanceState(Bundle outState) {
    outState.putSerializable("locationInfos", mLocationInfoVector);

    super.onSaveInstanceState(outState);
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    if (savedInstanceState.getSerializable("locationInfos") != null) {
        @SuppressWarnings("unchecked")
        mLocationInfoVector= (Stack<LocationInfo>) savedInstanceState.getSerializable("locationInfos");
    }

    super.onRestoreInstanceState(savedInstanceState);
}

ADDED:

I forgot to attach exception log.
That is

java.lang.ClassCastException: java.util.ArrayList cannot be cast to java.util.Stack

Answer 1

I use next code to restore Vector:

objects = new Vector<Object>((Collection<Object>) state.getSerializable(EXTRA_OBJECTS));

It prevents java.lang.ClassCastException and saves elements order.

To restore Stack, you can use next code:

stack = new Stack<Object>();
stack.addAll((Collection<Object>) state.getSerializable(EXTRA_STACK));

It works due to Vector, Stack, ArrayList are extending Collection, and you can cast your serialized object to Collection and pass to Stack or Vector addAll() method.