mixster

public class primes
{

    public static void main(String[] args) {
        final long startTime = System.nanoTime();

        boolean[] composite = new boolean[25000001];

        int limit = /*sqrt(25000000)*/ 5000;

        for(int i = 2; i <= limit; i++)
            if(!composite[i]) {
                int o = i * 2 - 1;

                for(int j = i + o; j <= 25000000; j += o)
                    composite[j] = true;

            }

        final long endTime = System.nanoTime();

        for(int i = 2; i <= 25/*000000*/; i += 1)
            if (!composite[i])
                System.out.println(2 * i - 1);

        System.out.print(endTime - startTime);
        System.out.println(" ns");
    }

}