1 /*

     2  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 /*

    26  * Manual test

    27  */

    28 

    29 import java.lang.ref.*;

    30 

    31 public class Test7190310 {

    32   private static Object str = new Object() {

    33     public String toString() {

    34       return "The Object";

    35     }

    36 

    37     protected void finalize() throws Throwable {

    38       System.out.println("The Object is being finalized");

    39       super.finalize();

    40     }

    41   };

    42   private final static ReferenceQueue<Object> rq =

    43       new ReferenceQueue<Object>();

    44   private final static WeakReference<Object> wr =

    45       new WeakReference<Object>(str, rq);

    46 

    47   public static void main(String[] args)

    48       throws InterruptedException {

    49     Thread reader = new Thread() {

    50       public void run() {

    51         while (wr.get() != null) {

    52         }

    53         System.out.println("wr.get() returned null");

    54       }

    55     };

    56 

    57     Thread queueReader = new Thread() {

    58       public void run() {

    59         try {

    60           Reference<? extends Object> ref = rq.remove();

    61           System.out.println(ref);

    62           System.out.println("queueReader returned, ref==wr is "

    63               + (ref == wr));

    64         } catch (InterruptedException e) {

    65           System.err.println("Sleep interrupted - exiting");

    66         }

    67       }

    68     };

    69 

    70     reader.start();

    71     queueReader.start();

    72 

    73     Thread.sleep(1000);

    74     str = null;

    75     System.gc();

    76   }

    77 }

    78