1 /*
   2  * Copyright (c) 2013, 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  * @bug 8005698
  27  * @summary Check operation of jdk.map.useRandomSeed property
  28  * @run main CheckRandomHashSeed
  29  * @run main/othervm -Djdk.map.useRandomSeed=false CheckRandomHashSeed
  30  * @run main/othervm -Djdk.map.useRandomSeed=bogus CheckRandomHashSeed
  31  * @run main/othervm -Djdk.map.useRandomSeed=true CheckRandomHashSeed true
  32  * @author Brent Christian
  33  */
  34 import java.lang.reflect.Field;
  35 import java.util.Map;
  36 import java.util.HashMap;
  37 import java.util.LinkedHashMap;
  38 import java.util.Hashtable;
  39 import java.util.WeakHashMap;
  40 
  41 public class CheckRandomHashSeed {
  42     private final static String PROP_NAME = "jdk.map.useRandomSeed";
  43     static boolean expectRandom = false;
  44 
  45     public static void main(String[] args) {
  46         if (args.length > 0 && args[0].equals("true")) {
  47             expectRandom = true;
  48         }
  49         String hashSeedProp = System.getProperty(PROP_NAME);
  50         boolean propSet = (null != hashSeedProp)
  51                 ? Boolean.parseBoolean(hashSeedProp) : false;
  52         if (expectRandom != propSet) {
  53             throw new Error("Error in test setup: " + (expectRandom ? "" : "not " ) + "expecting random hashSeed, but " + PROP_NAME + " is " + (propSet ? "" : "not ") + "enabled");
  54         }
  55 
  56         testMap(new HashMap());
  57         testMap(new LinkedHashMap());
  58         testMap(new WeakHashMap());
  59         testMap(new Hashtable());
  60     }
  61 
  62     private static void testMap(Map map) {
  63         int hashSeed = getHashSeed(map);
  64         boolean hashSeedIsZero = (hashSeed == 0);
  65         
  66         if (expectRandom != hashSeedIsZero) {
  67             System.out.println("Test passed for " + map.getClass().getSimpleName() + " - expectRandom: " + expectRandom + ", hashSeed: " + hashSeed);                                
  68         } else {
  69             throw new Error ("Test FAILED for " + map.getClass().getSimpleName() + " -  expectRandom: " + expectRandom + ", hashSeed: " + hashSeed);                                
  70         }
  71     }
  72 
  73     private static int getHashSeed(Map map) {
  74         try {
  75             if (map instanceof HashMap || map instanceof LinkedHashMap) {
  76                 map.put("Key", "Value");
  77                 Field hashSeedField = HashMap.class.getDeclaredField("hashSeed");
  78                 hashSeedField.setAccessible(true);
  79                 int hashSeed = hashSeedField.getInt(map);
  80                 return hashSeed;
  81             } else {
  82                 map.put("Key", "Value");
  83                 Field hashSeedField = map.getClass().getDeclaredField("hashSeed");
  84                 hashSeedField.setAccessible(true);
  85                 int hashSeed = hashSeedField.getInt(map);
  86                 return hashSeed;
  87             }
  88         } catch(Exception e) {
  89             e.printStackTrace();
  90             throw new Error(e);
  91         }
  92     }
  93 }