[grenadier21]

Minecraft Java Edition is 100% Java, but it's also notoriously slow, and experiences lag spikes, which are often attributed to garbage collection. I think an OS written in a GC language can certainly have adequate latency and throughput, but I don't think Minecraft is a good example of that.

[pjmlp]

Mostly due to bad programming practices, as already discussed multiple times in gamming forums.