As you already know, Java 1.4 does not have generics, so
you should remove all use of generics, and you'll most likely need to add some casts to your code at the places where you get objects out of the ArrayList.
Remove the generics in line 6.
Add casts in lines 41, 42, 43, 52, 53, 57, 58; everywhere where you call get() on the ArrayList, you need to cast the result to Student.
Why do you need to use Java 1.4? That's an ancient version for which there has not been support from Oracle anymore for years.