java joinGroup invocation not working

Hello,

In matlab version 6.5.0180913a (R13) which have java version 1.3.1_01 I'm trying to listen to some multicast packet using Java function invocations.

When I'm executing the joinGroup method, I can't see any IGMP join on wireshark. There is no problem with matlab version 7.1.0.246 (R14 SP3) which have java version 1.5.0

Please assist what could be done.

Thank you!

connection=MulticastSocket(5555)
ipadd=InetAddress.getByName("225.255.10.10")
connection.joinGroup(ipadd)