RFR (XS) 8221307 : String.substring() OOB exception on start index reports improper information

Ivan Gerasimov ivan.gerasimov at oracle.com
Thu Aug 8 18:49:51 UTC 2019

Hi Roger!  Thanks for the comments!

On 8/8/19 6:50 AM, Roger Riggs wrote:
> Hi Ivan,
> To be consistent with other checks of the index, can you use the 
> checkIndex(index, length) method?
> The message it produces would be appropriate for both cases.
Unfortunately, checkIndex(int, int) wouldn't be appropriate here because 
it only allows index < length, while we need index <= length here.

I think it makes sense to adopt the suggestion from Claes and just 
delegate to substring(int,int).

> While you are there can you add a space after the comma
> in lines 3680 and 3691.
Yes, done.

> Is there an appropriate test?  There should be.

The substring() method is used across many regression tests, so we do 
have sanity checking.

I didn't think it's worth it to check for specific error message.

With kind regards,


> Thanks, Roger
> On 8/7/19 8:17 PM, Ivan Gerasimov wrote:
>> Hello!
>> The exception thrown by substring(int) may look confusing.
>> For example it produces "String index out of range: -1" when the 
>> index is length+1.
>> It is proposed to make the error message more clear, similar to what 
>> we have for substring(int, int).
>> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8221307
>> WEBREV: http://cr.openjdk.java.net/~igerasim/8221307/00/webrev/
>> Would you please help review?
With kind regards,
Ivan Gerasimov

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