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Date: Wed, 11 Jul 2012 08:45:35 +0000 (UTC)
From: "Krzysztof Nazarewski (JIRA)" <jira@apache.org>
To: issues@commons.apache.org
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Subject: [jira] [Comment Edited] (LANG-810) StringUtils.join() endIndex,
 bugged for loop
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    [ https://issues.apache.org/jira/browse/LANG-810?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13411325#comment-13411325 ] 

Krzysztof Nazarewski edited comment on LANG-810 at 7/11/12 8:45 AM:
--------------------------------------------------------------------

Basically {{endIndex}} takes values from 1 to array.length instead of from 0 to {{(array.length - 1)}}
In current state {{endIndex}} is "1-based index", not "0-based index" while Java language uses 0-based indexes, also previous argument {{startIndex}} is 0-based.

If you put valid index 0, the for loop won't run at all as it checks (i < endIndex) like it was array's length.

Let's say you have 1 element array to join (it does not make practical sense, bu should work), it has index 0 and does not have anything beyond 0 index. 
According to JavaDoc only possible combination of startIndex and endIndex would be (0,0).
StringUtils.java, line 3394: {{for (int i = startIndex; i < endIndex; i++) {}}
However for loop will not execute even single time because {{(i = startIndex = 0)}} is not lower than {{(endIndex = 0)}}, it is equal to endIndex and the result of joining single element array from it's only index 0 to index 0 will be empty string.

Therefore to join that one-element array you need to use combination {{(startIndex = 0, endIndex = 1)}}, where {{(endIndex == array.length)}} is error according to JavaDoc:
"endIndex - the index to stop joining from (exclusive). *It is an error to pass in an end index past the end of the array*"


      was (Author: drag0nius):
    Basically endIndex takes values from 1 to array.length instead of from 0 to {{(array.length - 1)}}
In current state it is "1-based index", not "0-based index" while Java language uses 0-based indexes, also previous argument "startIndex" is 0-based.

If you put valid index 0, the for loop won't run at all as it checks (i < endIndex) like it was array's length.

Let's say you have 1 element array to join (it does not make practical sense, bu should work), it has index 0 and does not have anything beyond 0 index. 
According to JavaDoc only possible combination of startIndex and endIndex would be (0,0).
StringUtils.java, line 3394: {{for (int i = startIndex; i < endIndex; i++) {}}
However for loop will not execute even single time because {{(i = startIndex = 0)}} is not lower than {{(endIndex = 0)}}, it is equal to endIndex and the result of joining single element array from it's only index 0 to index 0 will be empty string.

Therefore to join that one-element array you need to use combination {{(startIndex = 0, endIndex = 1)}}, where {{(endIndex == array.length)}} is error according to JavaDoc:
"endIndex - the index to stop joining from (exclusive). *It is an error to pass in an end index past the end of the array*"


> StringUtils.join() endIndex, bugged for loop
> --------------------------------------------
>
>                 Key: LANG-810
>                 URL: https://issues.apache.org/jira/browse/LANG-810
>             Project: Commons Lang
>          Issue Type: Bug
>          Components: lang.*
>    Affects Versions: 3.1
>            Reporter: Krzysztof Nazarewski
>            Assignee: Joerg Schaible
>   Original Estimate: 1m
>  Remaining Estimate: 1m
>
> endIndex is described as index, but for loop still checks it as "array length".
> Basically missing equal sign
> commons-lang3-3.1-sources.jar, StringUtils.java lines 3309, 3394:
>         for (int i = startIndex; i < endIndex; i++) {
> should be:
>         for (int i = startIndex; i <= endIndex; i++) {

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