Cuberite
A lightweight, fast and extensible game server for Minecraft
...The project was created as an alternative to the official Java-based server software with the goal of improving performance, efficiency, and flexibility. By using C++ instead of Java, Cuberite reduces memory consumption and CPU overhead while still allowing players using the standard Minecraft Java Edition client to connect and play. The software recreates core gameplay systems such as world generation, multiplayer networking, and commands while allowing extensive customization through a plugin system. One of its defining features is a Lua-based plugin API that allows developers to easily extend the server with custom features, commands, and gameplay mechanics. ...