DatagramChannel::disconnect throws IOException while DatagramSocket::disconnect does not. As a result, the DatagramChannel::socket adaptor which calls DatagramChannel::disconnect currently catches IOException and rethrows it as Error.

On the other hand, DatagramChannel::disconnect has been fixed to rebind the socket in those cases where the underlying platform `disconnect` changes the local socket address. This unfortunately introduce the possibility that `disconnect` will fail. DatagramChannel::disconnect may throw an IOException in that case and its API documentation has been updated to recommend closing the socket if that happens. See JDK-8231260 and JDK-8231259.

This means that the risk of the DatagramChannel::socket adapter throwing an Error has slightly increased. This is a bit hostile to clients of this API.

The proposal is to change the DatagramChannel::socket adapter to throw UncheckedIOException instead, and update the specification of DatagramSocket::disconnect to document that an implementation may throw UncheckedIOException, and to recommend closing the socket in that case, in much the same way that was done for DatagramChannel.