Java Program to Check Prime Number

public class PrimeCheck {
    public static void main(String[] args) {
        int num = 29;
        boolean flag = false;
        
        if (num == 0 || num == 1) {
            flag = true;
        }

        for (int i = 2; i <= num / 2; ++i) {
            // condition for nonprime number
            if (num % i == 0) {
                flag = true;
                break;
            }
        }

        if (!flag)
            System.out.println(num + " is a prime number.");
        else
            System.out.println(num + " is not a prime number.");
    }
}

29 is a prime number.