code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.Collections;
  
  /*
   * Copyright 2003 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     4339792
   * @summary Basic test for Collections.disjoint
   * @author  Josh Bloch
   *
   * @compile -source 1.5 Disjoint.java
   * @run main Disjoint
   */
  
  import java.util.*;
  
  public class Disjoint {
      final static int N = 20;
  
      public static void main(String args[]) {
          // Make an array of lists each of which shares a single element
          // with its "neighbors," and no elements with other lists in the array
          Random rnd = new Random();
          List[] lists = new List[N];
          int x = 0;
          for (int i = 0; i < N; i++) {
              int size = rnd.nextInt(10) + 2;
              List<Integer> list = new ArrayList<Integer>(size);
              for (int j = 1; j < size; j++)
                  list.add(x++);
              list.add(x);
              Collections.shuffle(list);
  
              lists[i] = list;
          }
  
          for (int i = 0; i < N; i++) {
              for (int j = 0; j < N; j++) {
                  boolean disjoint = (Math.abs(i - j) > 1);
                  List<Integer> a = (List<Integer>) lists[i];
                  List<Integer> b = (List<Integer>) lists[j];
  
                  if (Collections.disjoint(a, b) != disjoint)
                      throw new RuntimeException("A: " + i + ", " + j);
                  if (Collections.disjoint(new HashSet<Integer>(a), b)
                      != disjoint)
                      throw new RuntimeException("B: " + i + ", " + j);
                  if (Collections.disjoint(new HashSet<Integer>(a),
                                           new HashSet<Integer>(b)) != disjoint)
                      throw new RuntimeException("C: " + i + ", " + j);
              }
          }
      }
  }
  