[jira] [Commented] (LANG-1039) HashCodeBuilder.reflectionHashCode(Object object) returns always the same result for any array

["Duncan Jones (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LANG-1039?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14146299#comment-14146299 ] 

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

This method works by examining the fields of an object and creating a cumulative hashcode based upon them. Given that an array has no fields, this behaviour seems correct to me (albeit a little counter-intuitive).

If those arrays had been contained within an object (the normal use case), your results would not be observed. Your results are identical to what you'd see if you simply called {{HashCodeBuilder.reflectionHashCode(new Object())}}.

> 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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