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https://issues.apache.org/jira/browse/SPARK-2148?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Patrick Wendell updated SPARK-2148:
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Assignee: Andrew Ash
> Document custom class as key needing equals() AND hashcode()
> ------------------------------------------------------------
>
> Key: SPARK-2148
> URL: https://issues.apache.org/jira/browse/SPARK-2148
> Project: Spark
> Issue Type: Improvement
> Components: Documentation
> Affects Versions: 1.0.0
> Reporter: Andrew Ash
> Assignee: Andrew Ash
> Fix For: 1.0.1, 1.1.0
>
>
> Several support requests on user@ have been tracked down to using a custom
> class as the key in a {{groupByKey()}} or {{reduceByKey()}} that has a custom
> {{equals()}} method but not the corresponding custom {{hashCode()}} method.
> Let's add a note in the documentation that custom keys need both {{equals()}}
> and {{hashCode()}} overridden, never just {{equals()}}
> The right place for this addition might be as a sub-section or note in
> http://spark.apache.org/docs/latest/programming-guide.html#working-with-key-value-pairs
> It should probably include a link to
> http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html#hashCode()
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