模拟短消息接收和有关操作最多存储20条短消息所编写的程序应包含且不限于如下功能：①短消息接收如果短消息总数超出20条则删除最早的短消息。②短列表显示所有短消息。③阅读任意一条短消息。④删除任意一条短消息。⑤消除所有短消息。⑥具有操作功能菜单。请用Java语言编写

以下是使用Java语言编写的模拟短消息接收和相关操作的程序：

import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Scanner;

class Message {
    private String content;
    private Date timestamp;

    public Message(String content) {
        this.content = content;
        this.timestamp = new Date();
    }

    public String getContent() {
        return content;
    }

    public Date getTimestamp() {
        return timestamp;
    }
}

public class ShortMessageSystem {
    private static final int MAX_MESSAGES = 20;
    private List<Message> messages;

    public ShortMessageSystem() {
        messages = new ArrayList<>();
    }

    public void receiveMessage(String content) {
        if (messages.size() >= MAX_MESSAGES) {
            messages.remove(0);
        }
        Message message = new Message(content);
        messages.add(message);
    }

    public void displayMessages() {
        if (messages.isEmpty()) {
            System.out.println("No messages.");
        } else {
            for (int i = 0; i < messages.size(); i++) {
                Message message = messages.get(i);
                System.out.println("[" + i + "] " + message.getContent());
            }
        }
    }

    public void readMessage(int index) {
        if (index >= 0 && index < messages.size()) {
            Message message = messages.get(index);
            System.out.println("Message content: " + message.getContent());
            System.out.println("Received at: " + message.getTimestamp());
        } else {
            System.out.println("Invalid message index.");
        }
    }

    public void deleteMessage(int index) {
        if (index >= 0 && index < messages.size()) {
            messages.remove(index);
            System.out.println("Message deleted.");
        } else {
            System.out.println("Invalid message index.");
        }
    }

    public void deleteAllMessages() {
        messages.clear();
        System.out.println("All messages deleted.");
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        ShortMessageSystem sms = new ShortMessageSystem();

        while (true) {
            System.out.println("Short Message System");
            System.out.println("1. Receive a message");
            System.out.println("2. Display all messages");
            System.out.println("3. Read a message");
            System.out.println("4. Delete a message");
            System.out.println("5. Delete all messages");
            System.out.println("6. Exit");
            System.out.print("Enter your choice: ");

            int choice = scanner.nextInt();
            scanner.nextLine(); // Consume newline character

            switch (choice) {
                case 1:
                    System.out.print("Enter message content: ");
                    String content = scanner.nextLine();
                    sms.receiveMessage(content);
                    System.out.println("Message received.");
                    break;
                case 2:
                    sms.displayMessages();
                    break;
                case 3:
                    System.out.print("Enter message index: ");
                    int index = scanner.nextInt();
                    scanner.nextLine(); // Consume newline character
                    sms.readMessage(index);
                    break;
                case 4:
                    System.out.print("Enter message index: ");
                    int deleteIndex = scanner.nextInt();
                    scanner.nextLine(); // Consume newline character
                    sms.deleteMessage(deleteIndex);
                    break;
                case 5:
                    sms.deleteAllMessages();
                    break;
                case 6:
                    System.out.println("Exiting...");
                    System.exit(0);
                default:
                    System.out.println("Invalid choice. Please try again.");
            }

            System.out.println();
        }
    }
}

这个程序使用一个ShortMessageSystem类来模拟短消息系统。其中，Message类表示一条短消息，包含内容和时间戳。ShortMessageSystem类包含一个消息列表，通过receiveMessage方法接收短消息并进行存储，如果消息总数超过20条，则删除最早的消息。其他方法分别用于显示所有消息、阅读指定消息、删除指定消息和删除所有消息。

程序的main方法实现了一个简单的操作菜单，用户可以根据菜单选项执行相应的操作