I think the biggest thing is composition over inheritance, and try to put your state into a container like CDI (Using Scoped beans). If those design paradigms

I think the biggest thing is composition over inheritance, and try to put your state into a container like CDI (Using Scoped beans). If those design paradigms don't work, we've actually had a bit of luck using BPMN and executing it via Drools. This is not "easy" per say but our processes and decision tree were not simple either. Wishing there was a simpler and modern BPMN like language that supported CDI directly.