How to check whether a given integer is prime number or not

//Define the functional interface with SAM 'Checkprime'
interface Checkprime {
	public boolean prime(int tmp);
}

public class PrimenumberLambda {
 
    public static void main(String[] args) {
         
        System.out.println("OUTPUT:");
        
        /* Define the Lambda expression for the functional interface 'Checkprime' */
        Checkprime Cp = ((num) -> {
        	
        	//Initialize the lower and upper boundary values in the for loop
        	int bvalToCheck = (int) Math.sqrt(num);
            for(int i=2;i<=bvalToCheck;i++)
                if(num%i==0) 
                	return false;
            return true;
		});
        
        System.out.println(41 +" is prime (true/false): "+Cp.prime(41));
        System.out.println(341 +" is prime (true/false): "+Cp.prime(341));
        System.out.println(441 +" is prime (true/false): "+Cp.prime(441));
        System.out.println(541 +" is prime (true/false): "+Cp.prime(541));
     }
}