If you can separate areas of functionality, you can upgrade it piece-by-piece. So while it starts off as 98% inscrutable assembly-in-Java, you transform it over

If you can separate areas of functionality, you can upgrade it piece-by-piece. So while it starts off as 98% inscrutable assembly-in-Java, you transform it over time until it's only 2%. Ideally, backed with strong tests and fuzzing.