The return(null) statement  has to be included since
the compiler has to be sure that the method  returns
_some_ object.
In case your method throws an exception, the return
Class.forName... is not executed and the callee gets
unexpected behaviour (if the 2nd return  statement is
not there). To prevent this, your method has to have a
foolproof return statement which will be executed no
matter what.
Incidentally, if you remove the return(null)
statement, the compiler gives an error.