RFR: JDK-8011136 - FileInputStream.available and skip inconsistencies

Dan Xu dan.xu at oracle.com
Wed May 15 18:04:08 UTC 2013

On 05/13/2013 06:25 AM, Alan Bateman wrote:
> On 10/05/2013 22:20, Dan Xu wrote:
>> Hi,
>> The FileInputStream.available() method can return a negative value 
>> when the file position is beyond the endof afile. This is an 
>> unspecified behaviour that has the potential to break applications 
>> that expect available to return a value of 0 or greater. The 
>> FileInputStream.skip(long) method allows a negative value as its 
>> parameter. This conflicts with the specifications of InputStream and 
>> FileInputStream classes.
>> They are both long standing behaviours. In the fix, available() has 
>> been changed to only return 0 or positive values. And for the 
>> skip(long) method, due to the compatibility concern, its behaviour 
>> will not be changed. Instead, the related java specs are going to be 
>> changed to describe its current behaviour.
>> bug: http://bugs.sun.com/view_bug.do?bug_id=8011136
>> webrev: http://cr.openjdk.java.net/~dxu/8011136/webrev.00/
>> Thanks for your review!
>> -Dan
> Thanks for following up on this one. Overall I agree with the 
> approach, it specifies skip to match long standing behavior and fixes 
> available to not return negative values.
> Just on wording, it might be better if the new statement in 
> InputStream.skip didn't start with "But". How about "Subclasses may 
> ..." as this would be consistent with exiting wording in this class.
> For FileInputStream then the statement on how "available" behaves 
> should probably move to the available javadoc. Something like "Returns 
> 0 when the file position is beyond EOF" should be fine.
> -Alan.
Thanks for your review, I have updated wordings in the java doc. The new 
webrev can be reviewed at 


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