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