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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 /*
  26  * @test
  27  * @bug 8196869
  28  * @summary Make sure we deal with internal Key data being cleared properly
  29  * @run main/othervm -Xms16m -Xmx16m -esa SoftKeys
  30  */
  31 import java.util.*;
  32 
  33 public class SoftKeys {
  34 
  35     private static final char[] CHARS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
  36 
  37     public static void main(String[] args) {
  38         try {
  39             // With 4 characters in "language", we'll fill up a 16M heap quickly,
  40             // causing full GCs and SoftReference reclamation. Repeat at least two
  41             // times to verify no NPEs appear when looking up Locale's whose
  42             // softly referenced data in sun.util.locale.BaseLocale$Key might have
  43             // been cleared.
  44             for (int i = 0; i < 2; i++) {
  45                 for (int j = 0; j < 512*1024; j++) {
  46                     new Locale(langForInt(j), "", "");
  47                 }
  48             }
  49         } catch (OutOfMemoryError e) {
  50             // Can happen on some system configurations, and while increasing heap
  51             // size would allow GC to keep up, it makes it impractically hard to
  52             // reproduce NPE issues that could arise when references are being
  53             // cleared. Do a System.gc() to try to reclaim enough memory to not
  54             // throw an OOME again in the jtreg wrapper.
  55             System.gc(); 
  56         } 
  57     }
  58 
  59     private static String langForInt(int val) {
  60         StringBuilder buf = new StringBuilder(4);
  61         buf.append(CHARS[(val >> 12) & 0xF]);
  62         buf.append(CHARS[(val >>  8) & 0xF]);
  63         buf.append(CHARS[(val >>  4) & 0xF]);
  64         buf.append(CHARS[(val >>  0) & 0xF]);
  65         return buf.toString();
  66     }
  67 }
  68