Funny, the general sentiment about Minecraft's backend was the exact opposite back when I was doing server hosting a number of years ago. Maybe that's changed t

Funny, the general sentiment about Minecraft's backend was the exact opposite back when I was doing server hosting a number of years ago. Maybe that's changed though. At the time at least, it was very clear that Minecraft was written for single player in mind. Nearly everything ran in a single main loop, causing virtually every multiplayer server to only be able to utilized 1 core. This meant most servers couldn't scale beyond ~50 players with vanilla Minecraft. Community optimizations could take this to 200-300, but usually sacrificed something for those performance gains. Then a ton of work went into workarounds like Bungee, which enabled the next-gen Minecraft servers to host thousands of players on a "single" logical server. Of course, the main game loop was actually still single threaded and those thousands of players couldn't truly interact with each other as you would expect with vanilla Minecraft.