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 4190323
   * @summary EMPTY_SET, EMPTY_LIST, and the collections returned by
   *          nCopies and singleton were spec'd to be serializable, but weren't.
   */
  
  import java.io.*;
  import java.util.*;
  
  public class Ser {
      public static void main(String[] args) throws Exception {
  
          try {
              ByteArrayOutputStream bos = new ByteArrayOutputStream();
              ObjectOutputStream out = new ObjectOutputStream(bos);
              out.writeObject(Collections.EMPTY_SET);
              out.flush();
              ObjectInputStream in = new ObjectInputStream(
                      new ByteArrayInputStream(bos.toByteArray()));
  
              if (!Collections.EMPTY_SET.equals(in.readObject()))
                  throw new RuntimeException("empty set Ser/Deser failure.");
          } catch (Exception e) {
              throw new RuntimeException("Failed to serialize empty set:" + e);
          }
  
          try {
              ByteArrayOutputStream bos = new ByteArrayOutputStream();
              ObjectOutputStream out = new ObjectOutputStream(bos);
              out.writeObject(Collections.EMPTY_LIST);
              out.flush();
              ObjectInputStream in = new ObjectInputStream(
                      new ByteArrayInputStream(bos.toByteArray()));
  
              if (!Collections.EMPTY_LIST.equals(in.readObject()))
                  throw new RuntimeException("empty list Ser/Deser failure.");
          } catch (Exception e) {
              throw new RuntimeException("Failed to serialize empty list:" + e);
          }
  
          try {
              ByteArrayOutputStream bos = new ByteArrayOutputStream();
              ObjectOutputStream out = new ObjectOutputStream(bos);
              Set gumby = Collections.singleton("gumby");
              out.writeObject(gumby);
              out.flush();
              ObjectInputStream in = new ObjectInputStream(
                      new ByteArrayInputStream(bos.toByteArray()));
  
              if (!gumby.equals(in.readObject()))
                  throw new RuntimeException("Singleton Ser/Deser failure.");
          } catch (Exception e) {
              throw new RuntimeException("Failed to serialize singleton:" + e);
          }
  
          try {
              ByteArrayOutputStream bos = new ByteArrayOutputStream();
              ObjectOutputStream out = new ObjectOutputStream(bos);
              List gumbies = Collections.nCopies(50, "gumby");
              out.writeObject(gumbies);
              out.flush();
              ObjectInputStream in = new ObjectInputStream(
                      new ByteArrayInputStream(bos.toByteArray()));
  
              if (!gumbies.equals(in.readObject()))
                  throw new RuntimeException("nCopies Ser/Deser failure.");
          } catch (Exception e) {
              throw new RuntimeException("Failed to serialize nCopies:" + e);
          }
      }
  }
  