public class PrimeExample {

    public static void main(String args[]) {

        final int numberToBeChecked = 3;//it is the number to be checked

        boolean isPrime = isPrime(numberToBeChecked);

        if (isPrime) {
            System.out.println(numberToBeChecked + " is prime number");
        } else {
            System.out.println(numberToBeChecked + " is not prime number");
        }
    }

    protected static boolean isPrime(final int numberToBeChecked) {
        boolean isPrime = false;
        if (numberToBeChecked == 0 || numberToBeChecked == 1) {
            isPrime = false;
        } else {
            boolean foundFactor = false;
            int largestDivisorToTry = numberToBeChecked / 2;
            for (int divisor = 2; divisor <= largestDivisorToTry; divisor++) {
                if (numberToBeChecked % divisor == 0) {
                    isPrime = false;
                    foundFactor = true;
                    break;
                }
            }
            if (!foundFactor) {
                isPrime = true;
            }
        }//end of else
        return isPrime;
    }
}