jMud is a Multi-User Dungeon (MUD) server framework that is intended to be extensible and with easily-defined game content.

Java-Based MUD server framework:
jMud is written in Java and creates a multi-threaded socket-based MUD server running on a specified port when launched. It should be capable of handling any number of connections, hardware allowing.

Extensible:
jMud defines interfaces that allow for creating entirely new game systems in Java. This allows the base framework to be built out to support any desired gameplay. Extensions are modular and can be applied in any combination, allowing for a highly-customizable MUD server. Documentation on writing these extensions is available and highly detailed.

Easily defined game content:
jMud defines the game world using YAML files, allowing for a simple, standard, human-readable way to create new rooms, items, mobs, scenery, and more. Furthermore, definition files are interpreted on-the-fly and cached, with simple admin commands to apply new content to a running server without restart. In-game player commands that write these YAML files are availble, with fine-grained authorization over access and application of new content to the server.