1 /*
   2  * Copyright (c) 2015, 2016, 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  * @test
  26  * @requires vm.compMode != "Xcomp"
  27  * @bug 8058897
  28  * @library /testlibrary
  29  * @modules java.base/sun.misc
  30  *          java.management
  31  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:MallocMaxTestWords=100m Reallocate
  32  */
  33 
  34 import jdk.test.lib.*;
  35 import sun.misc.Unsafe;
  36 import static jdk.test.lib.Asserts.*;
  37 
  38 public class Reallocate {
  39     public static void main(String args[]) throws Exception {
  40         Unsafe unsafe = Utils.getUnsafe();
  41 
  42         long address = unsafe.allocateMemory(1);
  43         assertNotEquals(address, 0L);
  44 
  45         // Make sure we reallocate correctly
  46         unsafe.putByte(address, Byte.MAX_VALUE);
  47         address = unsafe.reallocateMemory(address, 2);
  48         assertNotEquals(address, 0L);
  49         assertEquals(unsafe.getByte(address), Byte.MAX_VALUE);
  50 
  51         // Reallocating with a 0 size should return a null pointer
  52         address = unsafe.reallocateMemory(address, 0);
  53         assertEquals(address, 0L);
  54 
  55         // Reallocating with a null pointer should result in a normal allocation
  56         address = unsafe.reallocateMemory(0L, 1);
  57         assertNotEquals(address, 0L);
  58         unsafe.putByte(address, Byte.MAX_VALUE);
  59         assertEquals(unsafe.getByte(address), Byte.MAX_VALUE);
  60 
  61         // Make sure we can throw an OOME when we fail to reallocate due to OOM
  62         try {
  63             unsafe.reallocateMemory(address, 100 * 1024 * 1024 * 8);
  64         } catch (OutOfMemoryError e) {
  65             // Expected
  66             return;
  67         }
  68         throw new RuntimeException("Did not get expected OOM");
  69     }
  70 }