1 /*

     2  * Copyright (c) 2014, 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 sun.hotspot.WhiteBox;

    25 

    26 class AllocateBeyondMetaspaceSize {

    27   public static Object dummy;

    28 

    29   public static void main(String [] args) {

    30     if (args.length != 2) {

    31       throw new IllegalArgumentException("Usage: <MetaspaceSize> <YoungGenSize>");

    32     }

    33 

    34     long metaspaceSize = Long.parseLong(args[0]);

    35     long youngGenSize = Long.parseLong(args[1]);

    36 

    37     run(metaspaceSize, youngGenSize);

    38   }

    39 

    40   private static void run(long metaspaceSize, long youngGenSize) {

    41     WhiteBox wb = WhiteBox.getWhiteBox();

    42 

    43     long allocationBeyondMetaspaceSize  = metaspaceSize * 2;

    44     long metaspace = wb.allocateMetaspace(null, allocationBeyondMetaspaceSize);

    45 

    46     triggerYoungGC(youngGenSize);

    47 

    48     wb.freeMetaspace(null, metaspace, metaspace);

    49   }

    50 

    51   private static void triggerYoungGC(long youngGenSize) {

    52     long approxAllocSize = 32 * 1024;

    53     long numAllocations  = 2 * youngGenSize / approxAllocSize;

    54 

    55     for (long i = 0; i < numAllocations; i++) {

    56       dummy = new byte[(int)approxAllocSize];

    57     }

    58   }

    59 }