Craft Server is a pure minecraft server-side implementation based upon the reverse-engineered protocol specifications found here. It makes no use of Minecraft Java Edition, nor is any of its source code based upon knowledge of Java Edition's code. All efforts to create this project are done while avoiding any copyright infringement and uses publicly available data to assist with its creation. This server is designed in C++ using Stardust Engine and runs on Windows/Linux/Mac/PSP. It also has planned future support for the PS Vita and PS2, maintained by MotoLegacy and TBS-Frain-Breeze respectively.
Craft Server is not made in any part by Mojang nor represents Mojang's original work Minecraft. It is a fan-made re-implementation for non-commercial use, and must never be sold.
Furthermore this implementation is a 100% clean room technique, with no knowledge of the original source code involved.
The only assets of Mojang AB used to derive this was the Data Generators found in Minecraft's server.jar, which is publicly available for download, and was transformed to a Protocol ID map to respect Minecraft's namespacing convention.