code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.concurrent.TimeUnit;
  
  /*
   * Copyright 2005-2006 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 5057341 6363898
   * @summary Basic tests for TimeUnit
   * @author Martin Buchholz
   */
  
  import java.io.*;
  import java.util.*;
  import java.util.concurrent.*;
  import static java.util.concurrent.TimeUnit.*;
  
  public class Basic {
      private static void realMain(String[] args) throws Throwable {
  
          for (TimeUnit u : TimeUnit.values()) {
              System.out.println(u);
              check(u instanceof TimeUnit);
              equal(42L, u.convert(42, u));
              for (TimeUnit v : TimeUnit.values())
                  if (u.convert(42, v) >= 42)
                      equal(42L, v.convert(u.convert(42, v), u));
              check(readObject(serializedForm(u)) == u);
          }
  
          equal(  24L, HOURS.convert       (1, DAYS));
          equal(  60L, MINUTES.convert     (1, HOURS));
          equal(  60L, SECONDS.convert     (1, MINUTES));
          equal(1000L, MILLISECONDS.convert(1, SECONDS));
          equal(1000L, MICROSECONDS.convert(1, MILLISECONDS));
          equal(1000L, NANOSECONDS.convert (1, MICROSECONDS));
  
          equal(  24L, DAYS.toHours(1));
          equal(  60L, HOURS.toMinutes(1));
          equal(  60L, MINUTES.toSeconds(1));
          equal(1000L, SECONDS.toMillis(1));
          equal(1000L, MILLISECONDS.toMicros(1));
          equal(1000L, MICROSECONDS.toNanos(1));
  
          long t0 = System.nanoTime();
          MILLISECONDS.sleep(3); /* See windows bug 6313903, might not sleep */
          long elapsedMillis = (System.nanoTime() - t0)/(1000L * 1000L);
          System.out.printf("elapsed=%d%n", elapsedMillis);
          check(elapsedMillis >= 0);
          /* Might not sleep on windows: check(elapsedMillis >= 3); */
          check(elapsedMillis < 1000);
  
          //----------------------------------------------------------------
          // Tests for serialized form compatibility with previous release
          //----------------------------------------------------------------
          byte[] serializedForm = /* Generated using tiger */
              {-84, -19, 0, 5, '~', 'r', 0, 29, 'j', 'a', 'v', 'a', '.',
               'u', 't', 'i', 'l', '.', 'c', 'o', 'n', 'c', 'u', 'r', 'r', 'e',
               'n', 't', '.', 'T', 'i', 'm', 'e', 'U', 'n', 'i', 't', 0, 0,
               0, 0, 0, 0, 0, 0, 18, 0, 0, 'x', 'r', 0, 14,
               'j', 'a', 'v', 'a', '.', 'l', 'a', 'n', 'g', '.', 'E', 'n', 'u',
               'm', 0, 0, 0, 0, 0, 0, 0, 0, 18, 0, 0, 'x',
               'p', 't', 0, 7, 'S', 'E', 'C', 'O', 'N', 'D', 'S', };
          check(Arrays.equals(serializedForm(SECONDS), serializedForm));
      }
  
      //--------------------- Infrastructure ---------------------------
      static volatile int passed = 0, failed = 0;
      static void pass() {passed++;}
      static void fail() {failed++; Thread.dumpStack();}
      static void fail(String msg) {System.out.println(msg); fail();}
      static void unexpected(Throwable t) {failed++; t.printStackTrace();}
      static void check(boolean cond) {if (cond) pass(); else fail();}
      static void equal(Object x, Object y) {
          if (x == null ? y == null : x.equals(y)) pass();
          else fail(x + " not equal to " + y);}
      public static void main(String[] args) throws Throwable {
          try {realMain(args);} catch (Throwable t) {unexpected(t);}
          System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
          if (failed > 0) throw new AssertionError("Some tests failed");}
      static byte[] serializedForm(Object obj) throws IOException {
          ByteArrayOutputStream baos = new ByteArrayOutputStream();
          new ObjectOutputStream(baos).writeObject(obj);
          return baos.toByteArray();
      }
      static Object readObject(byte[] bytes)
          throws IOException, ClassNotFoundException {
          InputStream is = new ByteArrayInputStream(bytes);
          return new ObjectInputStream(is).readObject();
      }
  }
  