package NotebookMenu;
public class Notebook2 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        String command = "";
        Helper helper = new Helper();

        while (!(command = input.nextLine()).equals("5")) {
            try {
                switch (command) {
                    case "1": {
                        error = "";
                        System.out.print("Enter name: ");
                        String name = input.nextLine();
                        ..........
                        Contacts contact = new Contacts(name, phoneNumber, email);
                        helper.addNewContact(contact);
                    }
                    break;

                    case "2": {
                        List<Contacts> list = helper.displayAllContacts();
                    }
                    break;

                    case "3": {       
                        String name = input.nextLine();
                        String result = helper.findContactByName(name);
                    }
                    break;

                    case "4": {       
                        String name = input.nextLine();
                        helper.removeContactByName(name);                
                    }
                    break;
                    case "5": {
                    }
                    break;
                    default:
                        error = "";
                        break;
                }
            } catch (Exception e) {
                System.out.println("Error occured.. Please, try again..");
            }
            System.out.println(error + "" + menu);
        };

        System.out.println("\nExit..");

    }
}

package notebook;

public class Contacts {

    private String name;
    private int phone;
    private String email;

    public Contacts(String name, int phone, String email) {
        this.name = name;
        this.phone = phone;
        this.email = email;
    }

   // тут всякие геттеры и сеттеры
    
    @Override
    public String toString(){
        return "Contact (Name: " + this.name + ", phone number: " + this.phone + ", E-mail: " + this.email + ")\n";
    }
}

public class Helper {

    private List<Contacts> contactsList;

    public Helper() {
        this.contactsList = new ArrayList<Contacts>();
    }

    public void addNewContact(Contacts contact) {
        this.contactsList.add(contact);
    }

    public List<Contacts> displayAllContacts() {
        String result;
        
        return contactsList;
    }

    public String findContactByName(String name) {
        String result = "";

        for (Contacts contact : contactsList) {
            if (contact.getName().equals(name)) {
                result = contact.toString();
                result += "\n" + this.contactsList.get(contactsList.indexOf(contact)).toString() + "\n";
            }
        }
        return result;
    }

    public void removeContactByName(String name) {

        contactsList.remove(name);
    }
}