Java Calander

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Scanner;

class Event {
    String name;
    LocalDateTime dateTime;

    public Event(String name, LocalDateTime dateTime) {
        this.name = name;
        this.dateTime = dateTime;
    }

    public String toString() {
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMMM d, yyyy 'at' h:mm a");
        return name + " on " + dateTime.format(formatter);
    }
}

class Main {
    static ArrayList<Event> events = new ArrayList<>();

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

        System.out.println("What is your name?");
        String name = kb.nextLine();
        System.out.println();
        System.out.println("Hello " + name + ".");
        System.out.println();

        while (true) { // loop back to the start
            if (events.size() == 0) {
                System.out.println("You have no events yet.");
                System.out.println("Please add an event.");
                System.out.println();
                addEvent(kb);
            } else {
                System.out.println();
                System.out.println("What do you wish to do?");
                System.out.println();
                System.out.println("add");
                System.out.println("remove");
                System.out.println("view all");
                System.out.println("exit");
                System.out.println();

                String choice = kb.nextLine();
                switch (choice) {
                    case "add":
                        addEvent(kb);
                        break;
                    case "remove":
                        removeEvent(kb);
                        break;
                    case "view all":
                        viewAllEvents();
                        break;
                    case "exit":
                        System.out.println();
                        System.out.println("Goodbye!");
                        return; // exit the program
                    default:
                        System.out.println("Invalid choice. Please try again.");
                        System.out.println();
                        break;
                }
            }
        }
    }

    public static void addEvent(Scanner kb) {
    System.out.println();
    System.out.println("Enter the name of the event:");
    String name = kb.nextLine();

    LocalDateTime dateTime = null;
    while (true) {
        try {
            System.out.println();
            System.out.println("Enter the date and time of the event in the format 'M/d/yyyy h:mm AM/PM' (press enter to skip):");
            String input = kb.nextLine().trim();
            if (!input.isEmpty()) {
                String pattern = "M/d/yyyy h:mm a";
                if (input.matches("\\d{1}/\\d{1}/\\d{4}\\s\\d{1}:\\d{2}\\s\\w{2}")) {
                    input = "0" + input;
                }
                DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
                dateTime = LocalDateTime.parse(input, formatter);
            }
            if (dateTime == null) {
                System.out.println();
                System.out.println("Event not added.");
                System.out.println();
                break;
            } else {
                Event event = new Event(name, dateTime);
                events.add(event);
                System.out.println();
                System.out.println("Event added: " + event.toString());
                break;
            }
        } catch (DateTimeParseException e) {
            System.out.println();
            System.out.println("Invalid date/time format. Please enter a date/time in the format 'M/d/yyyy h:mm AM/PM', for example '1/1/2022 01:30 PM'.");
        }
    }
}

    public static void removeEvent(Scanner kb) {
    System.out.println();
    System.out.println("Enter the name of the event you want to remove:");
    String name = kb.nextLine();

    boolean found = false;
    Iterator<Event> iterator = events.iterator();
    while (iterator.hasNext()) {
        Event event = iterator.next();
        if (event.name.equalsIgnoreCase(name)) {
            found = true;
            iterator.remove();
            System.out.println();
            System.out.println("Event removed: " + event.toString());
          System.out.println();
            break;
        }
    }

    if (!found) {
        System.out.println();
        System.out.println("No event found with the name '" + name + "'.");
    }
  }

    public static void viewAllEvents() {
    Scanner kb = new Scanner(System.in);

    if (events.size() == 0) {
        System.out.println("You have no events.");
    } else {
        System.out.println();
        System.out.println("How would you like the events to be sorted?");
        System.out.println();
        System.out.println("1. Alphabetically");
        System.out.println("2. Time");
        System.out.println("3. Cancel");
        System.out.println();

        String choice = kb.nextLine();
        switch (choice) {
            case "1":
                Collections.sort(events, new Comparator<Event>() {
                    @Override
                    public int compare(Event e1, Event e2) {
                        return e1.name.compareToIgnoreCase(e2.name);
                    }
                });
                break;
            case "2":
                Collections.sort(events, new Comparator<Event>() {
                    @Override
                    public int compare(Event e1, Event e2) {
                        return e1.dateTime.compareTo(e2.dateTime);
                    }
                });
                break;
            case "3":
                return;
            default:
                System.out.println("Invalid choice. Please try again.");
                System.out.println();
                break;
        }

        System.out.println("Your events:");
        System.out.println();

        for (Event event : events) {
            System.out.println(event.toString());
        }
    }
}