Java program explaining the generation of OTP(One Time Password)

// Java code to explain how to generate OTP

// Here we are using random() method of util
// class in Java
import java.util.*;

public class NewClass
{
static char[] OTP(int len)
{
System.out.println("Generating OTP using random() : ");
System.out.print("You OTP is : ");

// Using numeric values
String numbers = "0123456789";

// Using random method
Random rndm_method = new Random();

char[] otp = new char[len];

for (int i = 0; i < len; i++)
{
// Use of charAt() method : to get character value
// Use of nextInt() as it is scanning the value as int
otp[i] =
numbers.charAt(rndm_method.nextInt(numbers.length()));
}
return otp;
}
public static void main(String[] args)
{
int length = 4;
System.out.println(OTP(length));
}
}

The OTP we are generating will change every time. As we have used random() method to generate the OTP.
Output :

Generating OTP using random() : 
You OTP is : 5291