Feature of Geometry withId()

[DavidBrieden]

I'm trying to make a new Feature Object using your example in this file:
Feature f = Feature.of(polygon).withId(id)

this isn't working, because withId() is a method from the Feature Builder, not from the Feature.
Do I need to use a Builder Object to create a new Feature with an Id?
Is there a way to alter a Feature Object after it gets created?