Java 10 has added a GC interface—to provide a clean GC development interface so that GC developers and HotSpot developers don't struggle to develop new GCs, and can locate the functionality of existing GCs with ease.

To a certain extent, Epsilon validates the GC interface. Since it doesn't reclaim memory, it doesn't really need to implement the methods that require it to maintain objects to reclaim, remove, or copy them. So, it can just inherit the default implementation (which isn't supposed to do any work). Since it works, Epsilon has helped in testing VM interfaces.