Can't speak for Berkeley, but for our virtual graduation we just set a server property to put everyone in adventure mode on join. Adventure mode prevents you from breaking blocks or opening chests so the only thing you can do is walk around.

You can also set a certain radius around the spawn read only in the official server. I’m not sure what practical difference that would have vs adventure mode.

Haven't played Minecraft for years but even 8 years ago-ish there was a fairly mature ecosystem for server owners to control permissions to build/remove etc.

Even a few years into the game some of those mods were ridiculously good, thinking about it.

There are a few ways, the easiest and only way the vanilla Miencraft server implementation offers is to set everyone to adventure mode. Adeventure mode doesn't allow players to destroy blocks, but they can play blocks if you manage to get any.

More advanced server implementations like Spigot have a plugin api. There are plenty of popular plugins like WorldGuard that allow you to manage what players can to within a certain region. You can define a region in the world an allow or prevent players from destroying and placing blocks. You can also control other things like mob spawning, PvP, etc.

These server implementations have quite capable APIs and building plugins using them is actually a lot of fun. Its what originally brought me intro programming.

I learned Java because of CraftBukkit. For many teenagers, some even under the age of 10, Minecraft was their first experience in server administration.

From setting up game servers, optimizing settings so Java did not crash, installing plugins, setting up config files, maintaining backups, writing their own plugins, learning basic networking issues, dealing with abuse (griefers), etc... Minecraft has taught a generation a lot.