Minestom is an open-source Minecraft server development framework that allows developers to build custom Minecraft server software from scratch without relying on Mojang’s original server code. Instead of functioning as a traditional server implementation, Minestom acts as a lightweight library that provides the core networking and gameplay infrastructure needed to create Minecraft server applications.
An alternative/custom Minecraft server, written in Java, compatible with the original protocol. OpenCraft is built upon Apache MINA, SLF4J, Jython and XStream. The aim is to have features not in the official server distribution, like antigrief/scripting.