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From "Andor Molnar (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ZOOKEEPER-1990) suspicious instantiation of java Random instances
Date Fri, 23 Mar 2018 14:41:00 GMT

    [ https://issues.apache.org/jira/browse/ZOOKEEPER-1990?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16411491#comment-16411491
] 

Andor Molnar commented on ZOOKEEPER-1990:
-----------------------------------------

[~shralex]

I understand the Random(1) call in tests and why it's necessary to make this injectable in
StaticHostProvider.

The question is if tests are not involved why do you instantiate Random like this:
{code:java}
new Random(System.currentTimeMillis() ^ this.hashCode());
{code}
Instead of using the default constructor which gives better randomness.

> suspicious instantiation of java Random instances
> -------------------------------------------------
>
>                 Key: ZOOKEEPER-1990
>                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1990
>             Project: ZooKeeper
>          Issue Type: Bug
>    Affects Versions: 3.5.0
>            Reporter: Patrick Hunt
>            Assignee: Mark Fenes
>            Priority: Critical
>             Fix For: 3.5.4, 3.6.0
>
>
> It's not clear to me why we are doing this, but it looks very suspicious. Why aren't
we just calling "new Random()" in these cases? (even for the tests I don't really see it -
typically that would just be for repeatability)
> {noformat}
> ag "new Random[ \t]*\(" .
> src/java/main/org/apache/zookeeper/ClientCnxn.java
> 817:        private Random r = new Random(System.nanoTime());        
> src/java/main/org/apache/zookeeper/client/StaticHostProvider.java
> 75:       sourceOfRandomness = new Random(System.currentTimeMillis() ^ this.hashCode());
> 98:        sourceOfRandomness = new Random(randomnessSeed);
> src/java/main/org/apache/zookeeper/server/quorum/AuthFastLeaderElection.java
> 420:                rand = new Random(java.lang.Thread.currentThread().getId()
> src/java/main/org/apache/zookeeper/server/SyncRequestProcessor.java
> 64:    private final Random r = new Random(System.nanoTime());
> src/java/main/org/apache/zookeeper/server/ZooKeeperServer.java
> 537:        Random r = new Random(id ^ superSecret);
> 554:        Random r = new Random(sessionId ^ superSecret);
> src/java/test/org/apache/zookeeper/server/quorum/WatchLeakTest.java
> 271:        Random r = new Random(SESSION_ID ^ superSecret);
> src/java/test/org/apache/zookeeper/server/quorum/CommitProcessorTest.java
> 151:            Random rand = new Random(Thread.currentThread().getId());
> 258:            Random rand = new Random(Thread.currentThread().getId());
> 288:        Random rand = new Random(Thread.currentThread().getId());
> src/java/test/org/apache/zookeeper/test/StaticHostProviderTest.java
> 40:    private Random r = new Random(1);
> {noformat}



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