Otp Generator using LocalTime Library in java

CODE :

import java.util.*;

import java.time.*;

class Otpt{

public static void otp()

{

Scanner sc = new Scanner(System.in);

LocalTime t = LocalTime.now();

String time = t.toString();

String p = "";

        for (int i = 1; i < time.length(); i += 2) {

            p += String.valueOf((int) Math.pow(Character.getNumericValue(time.charAt(i)), 2));

        }

String tm = p.substring(4,8);

System.out.println("Your Otp is : "+tm);

System.out.print("Please Enter Otp : ");

String totp = sc.next();

if(tm.equals(totp)){

System.out.println("Otp Verification Successfull");}

else{

System.out.println("The otp u've entered is invalid");

otp();

}

}

public static void main(String args[])

{ otp();

}

}

Inputs and Outputs :