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Code for finding all prime number under a given number N

I will be using the Sieve of Eratosthenes algorithm as mentioned on the wiki.

The code is like this:

import java.util.Arrays;
import java.util.Scanner;

public class FindingPrime {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int n = Integer.parseInt(scanner.nextLine());

        boolean[] a = new boolean[n];
        Arrays.fill(a, true);

        int squareRoot = (int) Math.ceil(Math.sqrt(n));

        for (int i = 2; i < squareRoot; i++) {
            if (a[i]) {
                int square = i * i;
                for (int j = square; j < n; j = (j + i)) {
                    a[j] = false;
                }
            }
        }

        for (int i = 2; i < a.length; i++) {
            if (a[i]) {
                System.out.print(i + " ");
            }
        }
    }
}

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Some good links

https://www.html5rocks.com/en/tutorials/internals/howbrowserswork/ http://taligarsiel.com/ClientSidePerformance.html -- Client side performance tips https://ariya.io/ https://vertx.io/docs/ -- New exciting Framework, Must read. https://javaee.github.io/ -- Very good resource to see various javaee projects and explore enterprise architecture and design concepts. https://projects.eclipse.org/projects/ee4j -- Lots of interesting open source projects by eclipse http://openjdk.java.net/projects/mlvm/ -- the main project for supporting more dynamic languages to jvm. http://esprima.org/ -- EcmaScript parser http://c2.com/ppr/ and http://hillside.net/ -- Good place to learn patterns http://cr.openjdk.java.net/~briangoetz/lambda/Defender%20Methods%20v4.pdf https://validator.w3.org/nu/ -- This will validate your website css and js https://www.cellstream.com/intranet/reference-reading/faq/216-what-is-2-128.html http://shattered.io/ -- An example of SHA1 collision attack.