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Comment by ZeWaka | Hacker News Reader

To be fair, since 2019 Mojang has been providing the mappings instead of everyone having to use community-created ones.

Very few people use mojang mappings -- the two big modloaders, forge and fabric (and their derivatives) have their own mappings respectively, due to the restrictions of the mojang mappings. It's possible to use the mojang mappings, but much less common.

Ah, I was aware of the different Fabric (Yarn) mappings and internal names (due to the few mods like architectury) but I think Forge switched over to Mojang's?

> As of 1.16.5 [(2021)], Forge will be using Mojang’s Official Mappings, or MojMaps, for the forseeable future

Pretty sure this applies to NeoForge as well: https://neoforged.net/personal/sciwhiz12/what-are-mappings/

PaperMC exclusively uses Mojang mappings, and it's the most popular loader for server-side modding these days.

Paper isn’t a mod loader, it uses Fabric under the hood. Also, what makes you think it’s the most popular server? I thought it was fading. I switched my server from Paper to Fabric years ago.

I've recently been setting up a velocity server network for some friends and friends of friends, and I agree with your findings. I don't have much history on Forge vs Paper vs Fabric vs..... (and found it all very overwhelming, honestly) but from what I can tell, the popular sites like modrinth have communities way more focused around Forge/NeoForge.

Paper does seem to have it's own site for plugins, hangar or something? (Don't have my web history on this PC) but the community support doesn't seem nearly as fleshed out.

It is incredible though, before 1.21 the last time I played around with MC server hosting was probably around 1.8 days, when it seemed like you only had Bukkit and a few plugins for it

Paper is custom server software and could be easily argued to be a mod loader if you consider plugins to be mods (although it’s probably a weak argument since there’s no mixin support built-in, although some large servers have added mixin support to their own Paper forks). However, it does not use Fabric under the hood (it’s based on Bukkit/CraftBukkit). By playercount, it is the largest (custom, standalone) MC server software in the world.

You’re right, my bad, Spigot (from Bukkit), not Fabric. I got the impression it’s actually using ~~Fabric~~ Spigot code for this because you’re using plugins compiled for Spigot and both a paper.whatever and spigot.whatever config file, but after looking it up I see that they forked it.

I’m not really clear on mod vs plugin vs mixin, I was just trying to refer to whatever software does the decompilation work rather than just consuming APIs provided by projects that do.

Sounds like it’s correct that Paper didn’t do its own mod API, but incorrect that Paper doesn’t do its own decompilation work.

> By playercount, it is the largest (custom, standalone) MC server software in the world.

Do you have a source on this? Not trying to accuse you of anything, I just know that a few servers claim this, and don’t know if we have reliable numbers.

I tend to think the distinction between "plugins" and "server-side mods" is a little pointless these days. I would consider something a "mod" if it's in an environment where it can deeply touch Mojang code and completely transform it if needed. And before we ever had Fabric/Sponge mixins, we had reflection and ASM for doing just this. We still have that, and a lot of Paper plugins make extensive use of reflection - particularly libraries that reflect into netty to hook directly into the protocol are quite common.

It doesn't use Fabric under the hood, where did you hear that?

> Also, what makes you think it’s the most popular server?

Because it's the only server software that can actually scale and support a long-term server with feature and bugfix stability. Its popularity bears out in what hosting companies say people are most commonly using. Though I'm not sure if there is a specific publicly published statistic to point to to prove this - there is bStats global stats, but it is biased towards the Paper ecosystem.

Fabric is getting close with certain optimization and bugfixing mods, but it's still not there. Paper has a checklist of what optimizations and fixes must be included for a release to proceed, whereas Fabric ecosystem is still a hodgepodge of different things that are only available on specific Minecraft versions.

(Neo)Forge primarily use either mojmaps or Parchment, which are the Mojang mappings with some extra goodies like docstrings and parameter names

It took me a while to find how to obtain the official mappings, but this article seems to have instructions: https://minescript.net/mappings

According to the article, official mappings can be found here: https://piston-meta.mojang.com/mc/game/version_manifest_v2.j...

They're also linked on the wiki page for each release, along with links to the client and server jars: https://minecraft.wiki/w/Java_Edition_1.21.5

Why do they obfuscate if they're just going to provide the mappings?

Well, maybe that's why they're not obfuscating anymore.

Proguard can also apply optimizations while it obfuscates. I think a good JVM will eventually do most of them itself, but it can help code size and warm-up. I'm guessing as JVMs get better and everyone is less sensitive to file sizes, this matters less and less.

And there's no way to do only the optimisation part? Surely you could optimise without messing up class and method names..?

One of the biggest optimizations it offers is shrinking the size of the classes by obfuscating the names. If you're obfuscating the names anyway, there's no reason that the names have to be the same length.

"hn$z" is a heck of a lot smaller than "tld.organization.product.domain.concern.ClassName"

Yeah in some ways the obfuscation and mappings are similar to minification and sourcemaps in javascript.

And minification in JavaScript only reduces the amount of bytes that has to be sent over the wire, it doesn't improve runtime performance.

According to the v8 devs it also can increase parsing performance

> Our scanner can only do so much however. As a developer you can further improve parsing performance by increasing the information density of your programs. The easiest way to do so is by minifying your source code, stripping out unnecessary whitespace, and to avoid non-ASCII identifiers where possible.

https://v8.dev/blog/scanner

Sure, but that's also just in the category improving loading a bit. It doesn't have anything to do with runtime performance.

So we're not talking about runtime performance, but some minor improvement in loading times? I assume that once the JVM has read the bytecode, it has its own efficient in-memory structures to track references to classes rather than using a hash map with fully qualified names as keys

The names need to be stored somewhere because they are exposed to the program that way

They have to be stored somewhere, but they don't have to be what the JVM uses when it e.g performs a function call at runtime. Just having the names in memory doesn't slow down program execution.

At runtime this is going to be a branch instruction yes

Proguard was heavily influenced by the needs of early Android devices, where memory was at a real premium. Reducing the size of static tables of strings is a worthwhile optimisation in that environment

Okay but we're talking about Minecraft on desktops and laptops, where the relevant optimizations would be runtime performance optimizations, no?

Probably, but proguard tends to bundle the whole lot together

Even a hash map with fully qualified names as keys wouldn't be so bad because Stirng is immutable in Java, so the hash code can be cached on the object.

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