ประมวลผล username เพื่อแสดงผล

public class UserDisplay {
    public static void main(String[] args) {
        List usernames = new ArrayList<>();
        usernames.add("Alice123");
        usernames.add("BobTheCoder");
        usernames.add("CharlieDev");
        usernames.add("David99");

        // Convert list to Stream
        Stream stream = usernames.____();
        // Print each username
        stream.____(name -> System.out.println("User: " + name));
    }
}