Java Program of Prime Number

Prime Number: The number which is divisible only by itself and 1 (e.g. 2,3,5,7,11,13,17 etc.)

public class PrimeNum {

            public static void main(String[] args) {

                        Scanner sc = new Scanner(System.in);

                        System.out.println("Enter a number-->");

                        int num = sc.nextInt();

                        boolean b = true;

                        for (int p = 2; p <= num / 2; p++) {

                                    int prime = num % p;

                                    if (prime == 0) {

                                                b = false;

                                                break;

                                    }

                        }

                        if (b) {

                                    System.out.println("This is a prime number.");

                        } else {

                                    System.out.println("This is not a prime number.");

                        }

            }

}