util/Random/DistinctSeeds.java

/**
 * @test %I% %E%
 * @bug 4949279
 * @summary Independent instantiations of Random() have distinct seeds.
 */

import java.util.Random;

public class DistinctSeeds {
    public static void main(String[] args) throws Exception {
        // Strictly speaking, it is possible for these to randomly fail,
        // but the probability should be *extremely* small (< 2**-63).
        if (new Random().nextLong() == new Random().nextLong() ||
            new Random().nextLong() == new Random().nextLong())
            throw new RuntimeException("Random() seeds not unique.");
    }
}
Revision:	1.2
Committed:	Sat Nov 8 07:46:41 2003 UTC (20 years, 6 months ago) by jsr166
Branch:	MAIN
Changes since 1.1:	+6 -5 lines
Log Message:	Minor tweaks
#	User	Rev	Content
1	jsr166	1.1	/**
2	jsr166	1.2	* @test %I% %E%
3	jsr166	1.1	* @bug 4949279
4			* @summary Independent instantiations of Random() have distinct seeds.
5			*/
6
7			import java.util.Random;
8
9			public class DistinctSeeds {
10			public static void main(String[] args) throws Exception {
11	jsr166	1.2	// Strictly speaking, it is possible for these to randomly fail,
12			// but the probability should be extremely small (< 2**-63).
13			if (new Random().nextLong() == new Random().nextLong() \|\|
14			new Random().nextLong() == new Random().nextLong())
15			throw new RuntimeException("Random() seeds not unique.");
16	jsr166	1.1	}
17			}