you've got the Student object. The problem is that you are tr ying to print the Student object, and Student has not yet overridden the toString() method.
so, if you want to see student with:
System.out.println(s.get(i));
then Student needs a toString override.
If you want to check that you in fact have a student object, try calling one of its getter methods (I assume it has get and possibly set methods?).