code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.Random;
  
  /*
   * Written by Doug Lea with assistance from members of JCP JSR-166
   * Expert Group and released to the public domain, as explained at
   * http://creativecommons.org/licenses/publicdomain
   */
  
  /*
   * @test
   * @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.");
      }
  }
  