You are using java but want access to Javascript for various reasons. (Maybe you want to add scripting? Maybe you want to use a JS lib? Really sort of depends on the circumstance).
Using node/v8 requires another distributable and starting up a new process.
NodeJS has gone woke and supports Black Lives Matters. They also seem to have a history of social justice battles (as does the company behind V8 that NodeJS is based on, Google). I'm glad for alternatives.