Calculate Prime Numbers

package com.darwinsys;

/*

 * Compute prime numbers, after Knuth, Vol 1, Sec 1.3.2, Alg. "P". Unlike Knuth, I don't build table

 * formatting into computational programs; output is one per line. <p> Note that there may be more

 * efficient algorithms for finding primes. Consult a good book on numerical algorithms.

 * 

 * @author Ian Darwin

 */

public class Primes {

    /** The default stopping point for primes */

    public static final long DEFAULT_STOP = 600L; //4294967295L;

    /** The first prime number */

    public static final int FP = 2;

    static int MAX = 10000;

    public static void main(String[] args) {

	long[] prime = new long[MAX];

	long stop = DEFAULT_STOP;

	if (args.length == 1) {

	    stop = Long.parseLong(args[0]);

	}

	prime[1] = FP; // P1 (ignore prime[0])

	long n = FP + 1; // odd candidates

	int j = 1; // numberFound

	boolean isPrime = true; // for 3

	do {

	    if (isPrime) {

		if (j == MAX - 1) {

		    // Grow array dynamically if needed

		    long[] np = new long[MAX * 2];

		    System.arraycopy(prime, 0, np, 0, MAX);

		    MAX *= 2;

		    prime = np;

		}

		prime[++j] = n; // P2

		isPrime = false;

	    }

	    n += 2; // P4

	    for (int k = 2; k <= j && k < MAX; k++) { // P5, P6, P8

		long q = n / prime[k];

		long r = n % prime[k];

		if (r == 0) {

		    break;

		}

		if (q <= prime[k]) { // P7

		    isPrime = true;

		    break;

		}

	    }

	} while (n < stop); // P3

	for (int i = 1; i <= j; i++)

	    System.out.println(prime[i]);

    }

}