Covariant overrides on the Buffer Hierachy

[Richard Warburton]

Hi,

It looks to me like there are no obvious problems with changing the buffer
> subclasses to use covariant overrides. As Alan mentioned, one API was
> modified this way in 7, by Martin Buchholz. The discussion threads for this
> change are [2] and [3]. It looks like Martin considered additional
> covariant overrides, but ultimately backed off from this for a variety of
> incidental reasons; see [4]. There is a certain amount of work here above
> and beyond just changing the return types, but there don't appear to be any
> fundamental issues.


So I've put a patch on cr at
http://cr.openjdk.java.net/~rwarburton/buffer-overrides-0/. It also touches
a couple of other classes which have unnecessary casts in. Aside from being
a good idea, fixing the casts is also necessary due to -Werror.  Let me
know if I've missed anything or if there are any outstanding issues.

I think the bugs that this resolves are:

https://bugs.openjdk.java.net/browse/JDK-4774077
https://bugs.openjdk.java.net/browse/JDK-6451131

regards,

  Richard Warburton

  http://insightfullogic.com
  @RichardWarburto <http://twitter.com/richardwarburto>