Welcome to my nightmare.

To see listeners:

 # netstat -anp | grep LISTEN | less

 # nmap localhost

To use IPv4 instead of IPv6 in Eclipse, edit:

/home/jj5/.eclipse/org.eclipse.platform_3.8_155965261/configuration/config.ini

And add:

 # https://lists.debian.org/debian-java/2010/03/msg00073.html
 java.net.preferIPv4Stack=true

More to come…