[Enhancement] ListUtils#ofList method should return an immutable List instance

[mercyblitz]

ListUtils#ofList method simply delegates the creation of a list to Arrays.asList(Object...) method, as code:

    public static <E> List<E> ofList(E... elements) {
        return asList(elements);
    }

Actual, the returned list is not an immutable instance, it could change the element content at the specified index, like :

   List<String> values = ofList("1","2");
   values.set(0,"-1"); // values = [ "-1" , "2" ]