code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.Collections;
  
  /*
   * Copyright 2000 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 4323074
   * @summary Basic test for new rotate algorithm
   */
  
  import java.util.*;
  
  public class Rotate {
      // Should have lots of distinct factors and be > ROTATE_THRESHOLD
      static final int SIZE = 120;
  
      static Random rnd = new Random();
  
      public static void main(String[] args) throws Exception {
          List a[] = {new ArrayList(), new LinkedList(), new Vector()};
  
          for (int i=0; i<a.length; i++) {
              List lst = a[i];
              for (int j=0; j<SIZE; j++)
                  lst.add(new Integer(j));
              int totalDist = 0;
  
              for (int j=0; j<10000; j++) {
                  int dist = rnd.nextInt(200) - 100;
                  Collections.rotate(lst, dist);
  
                  // Check that things are as they should be
                  totalDist = (totalDist + dist) % SIZE;
                  if (totalDist < 0)
                      totalDist += SIZE;
                  int index =0;
                  for (int k=totalDist; k<SIZE; k++, index++)
                      if (((Integer)lst.get(k)).intValue() != index)
                          throw new Exception("j: "+j+", lst["+k+"]="+lst.get(k)+
                                              ", should be "+index);
                  for (int k=0; k<totalDist; k++, index++)
                      if (((Integer)lst.get(k)).intValue() != index)
                          throw new Exception("j: "+j+", lst["+k+"]="+lst.get(k)+
                                              ", should be "+index);
              }
          }
      }
  }
  