Eratosthenes.java

import java.util.Arrays;

public class Eratosthenes {
 private static final int MAX = 30;
 public static void main(String[] args) {

 boolean [] flag = new boolean[MAX];
 Arrays.fill(flag, true);
 eratosthenes(flag, MAX);
 for (int i = 2; i < flag.length; i++){
 if (flag[i]){
 System.out.println(i + " is prime number");
 }
 }
 }

 public static void eratosthenes(boolean[] flag, int k){
 for (int i = 2; i*i < k ; i++) {
 if (flag[i]){
 for (int j = i*i; j < k ; j+=i) {
 flag[j] = false;
 }
 }
 }
 }
}