new eratosthenes written in Java

Eratosthenes.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.ArrayList;

/**
 * Created with IntelliJ IDEA.
 * User: 橘博之
 * Date: 4/20/13
 * Time: 4:37 PM
 */
public class Eratosthenes {
    public static void main(String[] args) throws IOException {
        System.out.println("素数を列挙します、数値を入力してください");

        //初期化の処理
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String str = null;

        //例外処理
        try {
            str = reader.readLine();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        }
        int maxNum = Integer.parseInt(str);

        boolean[]primes = new boolean[maxNum];
        Arrays.fill(primes,true);

        //素数を求めるメソッド
        calculatePrimeNumbers(primes);

        //素数リストを作成
        ArrayList<Integer>primeNumbers = convertPrimeNumbersListFromArray(primes);

        for(int i :primeNumbers) System.out.print(i + " ");
    }

    public static void calculatePrimeNumbers(boolean[] primes) {
        for (int i = 2; i < primes.length; i++){
            if(primes[i]) for (int j = i + i; j < primes.length; j += i) primes[j] = false;
        }
    }

    public static ArrayList<Integer> convertPrimeNumbersListFromArray(boolean[] primes){
        ArrayList<Integer>numbers = new ArrayList<Integer>();
        for (int i = 2; i < primes.length; i ++){
            if(primes[i]) numbers.add(i);
        }
        return numbers;
    }
}