package com.itranswarp.learnjava;import java.util.*;/** * Learn Java from https://www.liaoxuefeng.com/ *  * @author liaoxuefeng */public class Main {    public static void main(String[] args) {        List<Message> received = List.of(            new Message(1, "Hello!"),            new Message(2, "发工资了吗？"),            new Message(2, "发工资了吗？"),            new Message(3, "去哪吃饭？"),            new Message(3, "去哪吃饭？"),            new Message(4, "Bye")        );        List<Message> displayMessages = process(received);        for (Message message : displayMessages) {            System.out.println(message.text);        }    }    static List<Message> process(List<Message> received) {        TreeSet<Message> removeRepeatedMessages = new TreeSet<>(received);        return removeRepeatedMessages.stream().toList();    }}class Message implements Comparable {    public final int sequence;    public final String text;    public Message(int sequence, String text) {        this.sequence = sequence;        this.text = text;    }    @Override    public int compareTo(Object o) {        if(o instanceof Message) {            return ((Message) o).text.compareTo(this.text);        }       return 0;    }}