`jaotc` integrates with the HotSpot VM, while Substrate VM provides its own runtime (GC etc.) and intentionally supports only a subset of the JVM features. FWI

`jaotc` integrates with the HotSpot VM, while Substrate VM provides its own runtime (GC etc.) and intentionally supports only a subset of the JVM features. FWIW, both use Graal as a compiler.