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 }