Success!!
Seems it is indeed a Java issue. Java 7 apparently brings support for IPv6, and to quote a user at the java.net forums:
"When you attempt to connect to an IPv4 address then under the covers it will use an IPv4-mapped IPv6 address."
The fix is to add an environment variable to force Java to use IPv4.
Environment variable "_JAVA_OPTIONS"
Value "-Djava.net.preferIPv4Stack=true"
Works perfectly now!