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

[Alan Bateman]

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".

-Alan