program logic of printing the prime numbers

Question

Can any body help to understand this java program?

It just prints prime numbers, as you enter how many you want and it works well.

class PrimeNumbers
{           


        

Answer 1

public class PrimeNumber {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    ArrayList a = new ArrayList();
    for (int i = 1; i <= 100; ++i) {
        if (isPrime(i))
            a.add(i);
    }
    System.out.println("List : " + a);

}

public static boolean isPrime(int value) {
    if (value <= 1)
        return false;


    if ((value % 2) == 0)
        return (value == 2);

    for (int i = 3; i <= value - 1; i++) {
        if (value % i == 0) {
            return false;             
        }
    }     

    return true;
}

}