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From "Duncan Jones (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LANG-1039) HashCodeBuilder.reflectionHashCode(Object object) returns always the same result for any array
Date Fri, 26 Sep 2014 11:30:35 GMT

    [ https://issues.apache.org/jira/browse/LANG-1039?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14149041#comment-14149041
] 

Duncan Jones commented on LANG-1039:
------------------------------------

Could you describe your use case in more detail? As I've explained, our expectation is for
this method to be used to help you override {{Object.hashCode()}} when creating your own class.
Consequently, we were not expecting to be passed an array as an argument.

It would be helpful to understand how you are trying to use it, so we can better decide if
this is a use case we want to support. If it is, we can look at altering the class behaviour.
If it's not, then we can look to improve the Javadocs to avoid similar confusion in the future.

> HashCodeBuilder.reflectionHashCode(Object object) returns always the same result for
any array
> ----------------------------------------------------------------------------------------------
>
>                 Key: LANG-1039
>                 URL: https://issues.apache.org/jira/browse/LANG-1039
>             Project: Commons Lang
>          Issue Type: Bug
>          Components: lang.builder.*
>    Affects Versions: 3.3.2
>         Environment: Windows 7, Java 6
>            Reporter: Bartosz Paszkowski
>
> HashCodeBuilder.reflectionHashCode(Object object) returns always the same result for
any array. The result is 17.
> There is no information in javadoc, that this method works in that way.
> The same situation in previous versions.
> *Example:*
> {code}
> public class HashCodeBuilderTest {
>     
>     public static void main(String[] args) {
>         
>         System.out.println(HashCodeBuilder.reflectionHashCode(new double[] {1, 1}));
>         System.out.println(HashCodeBuilder.reflectionHashCode(new double[] {2, 2}));
>         System.out.println(HashCodeBuilder.reflectionHashCode(new int[] {3, 3}));
>         System.out.println(HashCodeBuilder.reflectionHashCode(new int[] {4, 4}));
>         System.out.println(HashCodeBuilder.reflectionHashCode(new Long[] {5L, 5L}));
>         System.out.println(HashCodeBuilder.reflectionHashCode(new Double[] {null, null}));
>         System.out.println(HashCodeBuilder.reflectionHashCode(new Object[] {Boolean.FALSE,
1L, null}));
>         
>     }
> }
> {code}
> *Output:*
> {code}
> 17
> 17
> 17
> 17
> 17
> 17
> 17
> {code}
> *Fix example 1*
> First check if argument obj in HashCodeBuilder.reflectionHashCode(Object obj) is an array
and than use java.util.Arrays.hashCode(Object[] array)



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