How to find prime no.

 import java.io.*
 public class PrimeNo {
  public static void main(String args[]) {
   Console con = System.console();
   int num = Integer.parseInt(con.readLine());
   for(int i=2;i<=num/2;i++) {
    temp=num%i;
    if(temp==0) {
     isPrime=false;
     break;
    }
   }
   //If isPrime is true then the number is prime else not
   if(isPrime)
    System.out.println(num + " is Prime Number");
   else
    System.out.println(num + " is not Prime Number");
  }
 }