What will happen while Asynctask task is running ,when the Screen orientation is change?

Rotation of the screen will cause the current Activity to be destroyed and new one recreated. If an AsyncTask is running when this happens, it could give rise to two consequences:
1. The new Activity instance might waste valuable resources by firing up the background work again, unaware that the old AsyncTask is still running.
2. When the old AsyncTask eventually finishes, it will attempt to report its results back to the old Activity instance which has already destroyed.