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.
An IDE is no substitute for an Intelligent Developer.