Lead dev here. Yup, that's right. There are a few classes that we will be forced to implement in Go. We're fixated on keeping this number as low as possible, but Thread is one that is inescapable. Class is another inescapable one--if we're to support reflection, etc.
Correct, implementing the core libraries is actually a massive effort. You can't just take the Hotspot one because it is a massive cumbersome codebase and it would force your JVM to work like Hotspot internally. (Let's ignore for a moment the question whether that would even be legal)
