1 /*

     2  * Copyright (c) 2015, 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 import java.lang.ref.WeakReference;

    25 

    26 public class SafepointTestMain {

    27     public static byte[] garbage;

    28     public static volatile WeakReference<Object> weakref;

    29 

    30     public static void createweakref() {

    31         Object o = new Object();

    32         weakref = new WeakReference<>(o);

    33     }

    34 

    35     public static void main(String[] args) throws Exception {

    36         // Cause several safepoints to run GC to see safepoint messages

    37         for (int i = 0; i < 2; i++) {

    38             createweakref();

    39             while(weakref.get() != null) {

    40                 garbage = new byte[8192];

    41                 System.gc();

    42             }

    43         }

    44     }

    45 }