java stream api manupalation for arraylist of integer to comma sepertaed

import java.util.*;

import java.util.stream.Collectors;

class Main {

  public static void main(String[] args) {

   List<String> strings = new LinkedList<>();

     strings.add("Java");strings.add("is");

     strings.add("cool");

     String message = String.join(", ", strings);

     System.out.println(message);

      List<Integer> num = new LinkedList<>();

     num.add(2);

     num.add(5);

     num.add(7);

     String message1 =num.stream().map((gameId)-> gameId.toString()).collect(Collectors.joining(","));

     System.out.println(message1);

     //message returned is: "Java is cool"

  }

}

https://www.baeldung.com/java-string-with-separator-to-list