Java Programming

I get this warning below when working with ArrayList...it's only a warning not an error.my code is below

1)java.util.List resim_no = new ArrayList();

2)resim_no.add(SQL.sonuc.getString("Resim_No")); //this code is in a loop

3)String [] Aresim_no=(String[])resim_no.toArray(new String[resim_no.size()]);

2. and 3. codes makes that warning.And warning says;

Type safety: The method toArray(Object[]) belongs to the raw type List. References to generic
type List<E> should be parameterized

thanks