code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.Collections;
  
  /*
   * Copyright 1999 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 4224271
   * @summary A null Comparator is now specified to indicate natural ordering.
   */
  
  import java.util.*;
  
  public class NullComparator {
      public static void main(String[] args) throws Exception {
          List list = new ArrayList(100);
          for (int i=0; i<100; i++)
              list.add(new Integer(i));
          List sorted = new ArrayList(list);
          Collections.shuffle(list);
  
          Object a[] = list.toArray();
          Arrays.sort(a, null);
          if (!Arrays.asList(a).equals(sorted))
              throw new Exception("Arrays.sort");
          a = list.toArray();
          Arrays.sort(a, 0, 100, null);
          if (!Arrays.asList(a).equals(sorted))
              throw new Exception("Arrays.sort(from, to)");
          if (Arrays.binarySearch(a, new Integer(69)) != 69)
              throw new Exception("Arrays.binarySearch");
  
          List tmp = new ArrayList(list);
          Collections.sort(tmp, null);
          if (!tmp.equals(sorted))
              throw new Exception("Collections.sort");
          if (Collections.binarySearch(tmp, new Integer(69)) != 69)
              throw new Exception("Collections.binarySearch");
          if (!Collections.min(list, null).equals(new Integer(0)))
              throw new Exception("Collections.min");
          if (!Collections.max(list, null).equals(new Integer(99)))
              throw new Exception("Collections.max");
      }
  }
  