Java: Using different generics in Method and Class [duplicate]

I am using a generics wildcard for my class and also using the wildcard of list in one of my methods:

public class Example<E> {

    private E element;

    private ArrayList<String> createNewList() {
        return new ArrayList<>();
    }
}

when i try to use the Method:

List<String> myList = new Example().createNewList();

tells me when compiling with Xlint:unchecked

unchecked conversion
  required: List<String>
  found:    ArrayList

since my E-Type has nothing to do with the my createNewLists Generics < String>, why it tells me i dont have the required Type?

thanks in advance.

by the way - using:

List<String> myList = new Example<>().createNewList();

works perfectly fine. but why?