You can enable debug messages using the -Dcom.sun.sdp.debug flag. If you specify a file, the messages will be output to that file, otherwise the messages will go to standard output.

This first example shows sample messages printed to standard output:

% java -Dcom.sun.sdp.conf=sdp.conf -Dcom.sun.sdp.debug MyApplicaton
BIND to 192.168.0.1:5000 (socket converted to SDP protocol)
CONNECT to 129.156.232.160:80 (no match)
CONNECT to 192.168.0.2:80 (socket converted to SDP protocol)

This second example shows the output redirected to a file named debug.log:

% java -Dcom.sun.sdp.conf=sdp.conf -Dcom.sun.sdp.debug=debug.log MyApplication &
[1] 27310
% tail -f debug.log
BIND to 192.168.0.1:5000 (socket converted to SDP protocol)