Questions

1. Can you pass a Thread object to Executor.execute? Would such an invocation make sense?

Exercises

1. Compile and run BadThreads.java:

   /*
    * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    *
    *   - Redistributions of source code must retain the above copyright
    *     notice, this list of conditions and the following disclaimer.
    *
    *   - Redistributions in binary form must reproduce the above copyright
    *     notice, this list of conditions and the following disclaimer in the
    *     documentation and/or other materials provided with the distribution.
    *
    *   - Neither the name of Sun Microsystems nor the names of its
    *     contributors may be used to endorse or promote products derived
    *     from this software without specific prior written permission.
    *
    * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
    * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
    * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
    * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
    * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
    * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
    * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
    * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
    * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
    * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
    * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    */ 
   
   public class BadThreads {
   
       static String message;
   
       private static class CorrectorThread extends Thread {
   
           public void run() {
               try {
                   sleep(1000); 
               } catch (InterruptedException e) {}
               //Key statement 1:
               message = "Mares do eat oats."; 
           }
       }
   
       public static void main(String args[]) throws InterruptedException {
           (new CorrectorThread()).start();
           message = "Mares do not eat oats.";
           Thread.sleep(2000);
           //Key statement 2:
           System.out.println(message);
       }
   }
   

   The application should print out "Mares do eat oats." Is it guaranteed to always do this? If not, why not? Would it help to change the parameters of the two invocations of Sleep? Describe two ways to change the program to enforce such a guarantee.

2. Modify the producer-consumer example in Guarded Blocks to use a standard library class instead of the Drop class.

Check your answers.