You have two separate classes in your module:
Recursion
, which contains
fib
, and
Main
which contains the
main
method. You then try to call
fib
as if it is a member of the
Main
class, which it is not. It is a static method of the
Recursion
class. So you need to change the call in your
main
method to:
System.out.println(Recursion.fib(n));
You will need to do the same with
reverse
and
isPalindrome
.