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https://issues.apache.org/jira/browse/HADOOP-3383?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12703690#action_12703690
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Shevek commented on HADOOP-3383:
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bq. the whole 17/37 stuff comes from effective Java (page 37)
I believe my response in Hadoop-5272 explains why this is at least as much
superstition as anything. It was particularly fashionable in around 1997 when
the first drafts of many of these books were being written, but Sun have since
rewritten many of the libraries which call hashCode to use superior Mersenne
algorithms for distribution. You need only ensure that your hashCodes are
generally distinct, rather than attempting to spread them out modulo some
(assumed smallish) N.
> Redundant computation in hashCode() implemenation
> -------------------------------------------------
>
> Key: HADOOP-3383
> URL: https://issues.apache.org/jira/browse/HADOOP-3383
> Project: Hadoop Core
> Issue Type: Improvement
> Components: dfs
> Reporter: Tsz Wo (Nicholas), SZE
>
> In some hashCode() implementation (e.g. Block.hashCode()), the formula has
> the form
> {noformat}
> 37 * 17 + f(x),
> {noformat}
> where f( x ) is some function. Adding 37*17 to f( x ) shifts the value of f(
> x ). It is not effective to do shifting in hash functions. The computation
> is redundant.
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