Clearly this is not going to be a high performance thing. I'd be surprised if it is even close.
It seems the goals for this are purely academic and about figuring out how Java works. They'll probably just do a simple interpreter and not a JIT compiler. That would be good enough for a POC. Additionally, they already indicated that they'll use Go's garbage collector, which won't be setting speed records with this either. And Java's typical usage of memory might actually stress it out a bit. Then there is the standard library which is going to need plenty of support for things like Threads, IO, various synchronization primitives and locks, etc. Doing that in Go is going to be a bit interesting but probably doable. Alternatively, they might just interface with native code directly and bypass the Go ecosystem. They might even reuse some things from openjdk for that. Speaking of which, native code and JNI would need to be implemented anyway.
It seems the goals for this are purely academic and about figuring out how Java works. They'll probably just do a simple interpreter and not a JIT compiler. That would be good enough for a POC. Additionally, they already indicated that they'll use Go's garbage collector, which won't be setting speed records with this either. And Java's typical usage of memory might actually stress it out a bit. Then there is the standard library which is going to need plenty of support for things like Threads, IO, various synchronization primitives and locks, etc. Doing that in Go is going to be a bit interesting but probably doable. Alternatively, they might just interface with native code directly and bypass the Go ecosystem. They might even reuse some things from openjdk for that. Speaking of which, native code and JNI would need to be implemented anyway.