I'm not very familiar with Nashorn, but could they just create a thin Java compatibility layer and outsource the bulk of the work to V8? Are there license issues with shipping V8 alongside Java?
see: http://openjdk.java.net/projects/detroit/
speculation: It looks like he wants Nashorn dead from any angle? GraalJS and V8, lol
I can't wait for the first release of Detroit - very exciting!
The biggest problem is the latency, but yeah separate V8 works alright.
I would guess Graal has something to do with this housecleaning.