Review request for 6795561

[Xueming Shen]

looks good; approved.

Alan Bateman wrote:
> 6795561: (bf) CharBuffer.subSequence() uses wrong capacity value for 
> new buffer
>
> Iris, you might want to review this one. 
> CharBuffer#subSequence(start,end) is specified to return a char buffer 
> that has a position of position() + start, a limit of position() + 
> end, and a capacity of capacity(). For buffers created via 
> CharBuffer#allocate or char buffer views we've always generated code 
> that return a CharBuffer with a position of 0 and a limit and capacity 
> that is the length of the subsequence. To my knowledge this hasn't 
> been noticed, probably because it required casting the result to a 
> char buffer. In jdk7 this method has been updated to take advantage of 
> covariant returns so it's more likely to be noticed now. Furthermore, 
> your old adversary StringCharBuffer (used when wrapping a char 
> sequence) has been returning a buffer with the incorrect capacity 
> since 6546113 [1], leading to the IOOBE in the bug report. We should 
> have caught this but didn't. To that end, I've added coverage to the 
> unit test.
>
> The webrev is here:
>  http://cr.openjdk.java.net/~alanb/6795561/webrev.00/
>
> Thanks,
> Alan.
>
> [1] http://hg.openjdk.java.net/jdk7/tl/jdk/rev/c73cb47fe250