code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.concurrent.SynchronousQueue;
  
  /*
   * Copyright 2004-2008 Sun Microsystems, Inc.  All Rights Reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
   * CA 95054 USA or visit www.sun.com if you need additional information or
   * have any questions.
   */
  
  /*
   * @test
   * @bug 4992438 6633113
   * @summary Checks that fairness setting is respected.
   */
  
  import java.util.concurrent.*;
  import java.util.concurrent.locks.*;
  
  public class Fairness {
      private static void testFairness(boolean fair,
                                       final BlockingQueue<Integer> q)
          throws Throwable
      {
          final ReentrantLock lock = new ReentrantLock();
          final Condition ready = lock.newCondition();
          final int threadCount = 10;
          final Throwable[] badness = new Throwable[1];
          lock.lock();
          for (int i = 0; i < threadCount; i++) {
              final Integer I = i;
              Thread t = new Thread() { public void run() {
                  try {
                      lock.lock();
                      ready.signal();
                      lock.unlock();
                      q.put(I);
                  } catch (Throwable t) { badness[0] = t; }}};
              t.start();
              ready.await();
              // Probably unnecessary, but should be bullet-proof
              while (t.getState() == Thread.State.RUNNABLE)
                  Thread.yield();
          }
          for (int i = 0; i < threadCount; i++) {
              int j = q.take();
              // Non-fair queues are lifo in our implementation
              if (fair ? j != i : j != threadCount - 1 - i)
                  throw new Error(String.format("fair=%b i=%d j=%d%n",
                                                fair, i, j));
          }
          if (badness[0] != null) throw new Error(badness[0]);
      }
  
      public static void main(String[] args) throws Throwable {
          testFairness(false, new SynchronousQueue<Integer>());
          testFairness(false, new SynchronousQueue<Integer>(false));
          testFairness(true,  new SynchronousQueue<Integer>(true));
      }
  }
  