java check if a number is prime number

/**
 * @author lautturi.com
 * Java example:check if number is prime in java
 */

import java.util.*;

public class Lautturi {

	public static boolean isPrime(int num) {
		if (num < 2)
			return false;
		for (int i = 2; i <= Math.sqrt(num); i++) {
			if (num % i == 0)
				return false;
		}
		return true;
	}

	public static void main(String[] args) {

		System.out.println(isPrime(1234));
		System.out.println(isPrime(11));

	}
}

output:

false
true