RFR [9] 8157166: Update spec to account for platforms that do not support multicast

[Chris Hegarty]

> On 16 Jun 2016, at 16:31, Alan Bateman <Alan.Bateman at oracle.com> wrote:
> 
> On 16/06/2016 16:03, Chris Hegarty wrote:
> 
>> Some platforms do not support multicasting, but the current spec requires that
>> it is supported. It seems reasonable to relax this, somewhat, so that multicasting
>> is effectively optional on these platforms.
>> 
>> java.net.MulticastSocket.joinGroup and java.nio.channels.MulticastChannel.join
>> method specifications should be updated to indicate that an exception will be
>> thrown if invoked on a platform that does not support multicasting.
>> 
>> http://cr.openjdk.java.net/~chegar/8157166/
>> https://bugs.openjdk.java.net/browse/JDK-8157166
>> 
> This looks okay. For MultlicastChannel then "When IGMPv2 is supported then it may" might be clearer as " When IGMPv2 is supported then the operating system may".

Yes, that is better. Webrev updated in-place.

-Chris.