“Warning: [unchecked] unchecked cast” when casting Object to ArrayList

Question

Strange situation - below is the code:

ArrayList listArr = new ArrayList<>();
Object[] obj = new Object[]{\"str\", listArr};

String st         


        

Answer 1

This is because if you try to cast Integer to String you will get ClassCastException at runtime. But there will be no ClassCastException here:

    ArrayList listArr = new ArrayList<>();
    ArrayList list = (ArrayList) obj[1];