1 /*
   2  * Copyright (c) 2018, 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  * @test
  25  * @bug 8196869
  26  * @summary Make sure we deal with internal Key data being cleared properly
  27  * @run main/othervm -Xms16m -Xmx16m -esa SoftKeys
  28  * @ignore This test aims to provoke NPEs, but due to the need to constrain
  29  *         memory usage it fails intermittently with OOME on various systems
  30  *         with no way to ignore such failures.
  31  */
  32 import java.util.*;
  33 
  34 public class SoftKeys {
  35 
  36     private static final char[] CHARS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
  37 
  38     public static void main(String[] args) {
  39         try {
  40             // With 4 characters in "language", we'll fill up a 16M heap quickly,
  41             // causing full GCs and SoftReference reclamation. Repeat at least two
  42             // times to verify no NPEs appear when looking up Locale's whose
  43             // softly referenced data in sun.util.locale.BaseLocale$Key might have
  44             // been cleared.
  45             for (int i = 0; i < 2; i++) {
  46                 for (int j = 0; j < 512*1024; j++) {
  47                     new Locale(langForInt(j), "", "");
  48                 }
  49             }
  50         } catch (OutOfMemoryError e) {
  51             // Can happen on some system configurations, and while increasing heap
  52             // size would allow GC to keep up, it also makes it impractically hard
  53             // to reproduce NPE issues that could arise when references are being
  54             // cleared.
  55 
  56             // Do a System.gc() to not throw an OOME again in the jtreg wrapper.
  57             System.gc();
  58         }
  59     }
  60 
  61     private static String langForInt(int val) {
  62         StringBuilder buf = new StringBuilder(4);
  63         buf.append(CHARS[(val >> 12) & 0xF]);
  64         buf.append(CHARS[(val >>  8) & 0xF]);
  65         buf.append(CHARS[(val >>  4) & 0xF]);
  66         buf.append(CHARS[(val >>  0) & 0xF]);
  67         return buf.toString();
  68     }
  69 }
  70