cuberite VS Glowstone

You might be able to port a C/C++ implementation to Arduino or another language with a good ESP compiler, but that's going to be a lot of effort, and the biggest challenge you're going to face isn't RAM, it's disk space--Minecraft worlds can be GB in size, so you'll need to pair your microcontroller with, say, an SD card reader and then adapt a whole disk IO system

Shout out for Cuberite as an alternative Minecraft server project that desperately needs more volunteers

https://github.com/cuberite/cuberite

"Cuberite is a Minecraft-compatible multiplayer game server that is written in C++ and designed to be efficient with memory and CPU"

Cuberite has been demoed running on old ARM Android phones and hosting multiple players off it at once. Its performance absolutely annihilates the Java based 'vanilla' server

so basically Cuberite but more officially and with a rewritten client as well

Some have started doing this already, like Cuberite and McPy.

For minecraft server I guess it is worth trying this out: https://github.com/cuberite/cuberite

For the server you should look into Cuberite, same thing but for the server and written in C++.

There were a bunch of attempts in the past. Cuberite is still actively maintained but I have never tried them: https://github.com/cuberite/cuberite

Assuming you mean this Glowstone, you'll see they themselves acknowledge that "it is not ready for survival".

It's definitely not a realistic replacement for modded Minecraft in general, since that's really hundereds of games and Mineclone only aims to replace Minecraft itself. For modded, I'm not sure what the answer is. Even most third party clients/servers that are compatible with vanilla Minecraft don't support Forge mods. Stevenarella might support Forge to some extent, but I'm not sure how it works since Forge is written in Java and Stevenarella is written in Rust. I'm not aware of any third party servers that support Forge in any capacity, but Glowstone (which actually seems like a pretty good third party server by the way) does support Bukkit plugins.

Also to add to this, if you don't need full vanilla functionality and are more focus on higher player count than something slightly more experimental but more performant might be your best bet like GlowstoneMC (glowstone supports paper plugins) or Minestrom

You could. Glowstone is a Minecraft server written in Java (without any of Mojang's code) but it is still not feature complete from what I heard, so things are missing. When I tried it, it seemed pretty solid and fast though.

I forked a project [1] in 2015 to remove Gradle, and it then quickly subsumed the original project, remaining under active development to this day.

There were other reasons, but de-gradling was one of the main motivations for my fork, and among the first of the major changes I made. The project is an implementation of an API which was discontinued by the original developers, but initially was built using Maven.

After switching from Gradle (which the project switched to in 2014) back to Maven, build times significantly decreased and development became much more pleasant. I found Gradle to be like a speed bump slowing down development, and reverting back to Maven was like a breath of fresh air. Simple, straightforward, and fast. Maven may not be perfect, but it does the job well.

[1] An open source Bukkit server implementation, https://github.com/GlowstoneMC/Glowstone -> http://github.com/GlowstonePlusPlus/GlowstonePlusPlus