3 – Best Java program to check prime number

import java.util.*;
class Prime
{
    public static void main(String agr[])
    {
        int num;
        boolean p = true;
        Scanner in = new Scanner(System.in);
        System.out.println("Enter any number : ");
        num = in.nextInt();
        if(num == 1)
        {
            System.out.println("1 is not a prime or composite number");
        }
        for(int i=2; i <= num/2; i++)
        {
            if(num % i == 0)
            {
                p = false;
                System.out.println(num+" is not a prime number");
                break;
            }
        }
        if(p)
        {
            System.out.println(num+" is a prime number");
        }
    }
}