RFR: 8005051: default methods for Iterator

Chris Hegarty chris.hegarty at oracle.com
Fri Dec 14 11:46:57 UTC 2012

On 14/12/2012 01:24, Akhil Arora wrote:
> As part of the library lambdafication, this patch adds a forEach default
> method to Iterator, and converts remove() into a default method so that
> implementations of Iterator no longer have to override remove if they
> desire the default behavior, which is to throw an
> UnsupportedOperationException.

This is not specified. Different Java SE implementations can have 
different default implementations of remove(). Your statement is either 
mistaken, or the changes will not meet their original intent.

forEach, it is not clear to me if the method description is specifying 
what the default implementation is supposed to do, or if it is 
specifying the contract for the method.

This, of course, has the same underlying cause as what is being 
discussed in other mail threads. I would like to see a clear decision 
being made around how default methods are to be specified before we 
start moving them into jdk8.


> http://cr.openjdk.java.net/~akhil/8005051.0/webrev/
> The above patch requires a small patch to an internal class which
> happens to implement both Iterable and Iterator. Now both Iterable and
> Iterator supply a default forEach method, so the compiler balks. One
> minimally intrusive solution is for this class to override both defaults
> and provide its own version of forEach.
> http://cr.openjdk.java.net/~akhil/8005053.0/webrev/
> Please review
> Thanks

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