RandomBug.java

// Random number generation is hard! - Page 47
package org.effectivejava.examples.chapter08.item47;

import java.util.Random;

public class RandomBug {

	private static final Random rnd = new Random();

	// Common but deeply flawed!
	static int random(int n) {
		return Math.abs(rnd.nextInt()) % n;
	}

	public static void main(String[] args) {
		int n = 2 * (Integer.MAX_VALUE / 3);
		int low = 0;
		for (int i = 0; i < 1000000; i++)
			if (random(n) < n / 2)
				low++;

		System.out.println(low);
	}
}