android: problem with Serializable object put into intent

Hi i have problem with a class i want to pass in an intent by putting it into the putExtras() Its serializable and the code looks like this: ``` public abstract class ObjectA extends ArrayList<ObjectA> implements java.io.Serializable{...} public class ObjectB extends ObjectA {...} ... Bundle extras = new Bundle(); extras.putSerializable("blabla", ObjectB); intent.putExtras(extras); ... Object y = getIntent().getExtras().get("blabla"); ``` the problem is, that y now is an ArrayList and no longer an ObjectB so i cant cast it.. if i change the code to ``` public class ObjectB implements java.io.Serializable {...} ``` it works fine