Almost exclusively J2EE apps.
I am not saying there weren't any benefits from the JVM over the years only that the biggest gains I've experienced have come from new types of libraries.
Fully agree with Java 9 though. It is the first release that I've been really excited about. Project Jigsaw has the potential to fundamentally reimagine the entire platform.
They ship new optimisations in more or less every release. I'm not sure what workload you do that you've never seen performance improvements.
For example in Java 9 they're going to ship auto-vectorisation for certain kinds of functional / parallel stream construct.