A few questions/comments about java.net.MulticastSocket

[Daniel Fuchs]

Hi Vitaly,

On 19/01/2021 19:01, Vitaly Davidovich wrote:
>>     A few colleagues and I were trying to make sense of the
>>     joinGroup(SocketAddress, NetworkInterface)
>>     <https://github.com/openjdk/jdk/blob/05a764f4ffb8030d6b768f2d362c388e5aabd92d/src/java.base/share/classes/java/net/MulticastSocket.java#L382>
>>     method.  In particular:
>>
>>       * Why does this take a SocketAddress and then ignores the port
>>         in the implementation? Any reason it doesn't take InetAddress,
>>         which would make it clear the port is unnecessary? The
>>         deprecated overload of joinGroup takes an InetAddress (and is
>>         deprecated because it didn't allow specifying the network
>>         interface).
>>
>     That was an API mistake in Java 1.4. When DatagramChannel was
>     updated to support joining multicast groups (in Java 7) it was able
>     to get the parameters right.
> 
> Would it make sense to make a note of this aspect in joinGroup's javadoc?
> 

FWIW, the API documentation has been clarified in 17 by
https://bugs.openjdk.java.net/browse/JDK-8237352

I hope this will make things clearer.

best regards,

-- daniel