Helper.java

import java.util.Random;
import java.util.Scanner;

public class Helper {

    public static Scanner scanner = new Scanner(System.in);
    public static Random random = new Random();

    private static Integer getInt(String inputMessage, String errorMessage) {
        while(true){
            try {
                System.out.print(inputMessage);
                return Integer.parseInt(scanner.nextLine());
            } catch (NumberFormatException e) {
                System.err.println(errorMessage);
           }
        }
    }

    public static Integer getInt(String inputMessage) {
        return getInt(inputMessage, "\nError: el valor ingresado no es un entero");
    }

    private static Integer getPositiveInt(String inputMessage, String errorMessge) {
        while (true) {
            int num = getInt(inputMessage);
            if(num > 0) return num;
            System.err.println("\n" + errorMessge);
        }
    }

    public static Integer getPositiveInt(String inputMessage){
        return getPositiveInt(inputMessage, "\nError: el valor ingresado no es un entero positivo");
    }

    public static int randomInt(int min,int max) {
        return random.nextInt(max - min + 1) + min;
    }
}