Reduce a list of string add prefix only to last element using Java 8 Streams

How can i reduce or collect a list of string delimitted by comma and prefixed "and" only to the last element using Java 8 Streams?

eg.

List<String> ls = Arrays.asList("tom","terry","john","kevin","steve");

String result = ls.stream().map(String::toString)
                .collect(Collectors.joining(", "));

System.out.println(result);

This statement prints => tom, terry, john, kevin, steve. But i wanted to print the list as tom, terry, john, kevin and steve.

Two solutions.

Clumsy, taking sublist actually:

    String result = ls.stream()
            .limit(ls.size() - 1)
            .collect(Collectors.joining(", ")) + " and " + ls.get(ls.size() - 1);

Using a class to shift one place:

    class SbS {
        StringBuilder sb = new StringBuilder();
        String s = "";

        @Override
        public String toString() {
            return sb + (s.empty() ? "" : " and " + s);
        }
    }
    result = ls.stream()
            .collect(SbS::new,
                (a, s) -> {
                    a.sb.append(a.sb.length() == 0 ? "" : ", ").append(a.s); a.s = s;
                },
                (a1, a2) -> {}).toString();

Mind: the class definition should be placed inside the method, just as above. Otherwise static would be needed. The lambda for the (a, s) could be a method in SbS. The support for parallelism is left as excercise to the reader (a1, a1).