Checking Prime Number using Java

class Prime{
        public static void main(String args[])
        {
                int num=Integer.parseInt(args[0]),c=0;
                for(int i=2;i<=num/2;i++)
                        if(num%i==0)
                                c++;
                if(c==0)
                        System.out.println(num+" is a prime number.");
                else
                        System.out.println(num+" is not a prime number.");
        }
}