It has been suggested that the JDK should set IP_MULTICAST_ALL=0 to avoid interference caused when two sockets are bound to the same port but joined to different multicast groups. This is a long standing issue on Linux that has come up many times.

The thread on net-dev discussion this is:

http://mail.openjdk.java.net/pipermail/net-dev/2013-May/006246.html