Actually, for a short period of time, I had problems getting Tomcat to do
IPV4 requests.
Tomcat really doesn't care. It lets the
Java network stack worry about that for the most part. However, there was a brief interval several years back where JVMs were shipped with IPV6 enabled by default and an explicit JVM parameter had to be set or
all network-aware Java apps ran IPV6-only by default.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.