L2JMobius, charted.
A whiteboard walk through the architecture, the install, the history and the law - the four corners of L2JMobius in one place.
Built for engineers who want the shape of the codebase before they read the code, and for operators who want to know exactly what they're standing on.
What is L2JMobius?
L2JMobius is a Java-based, open-source Lineage 2 server emulator. It is the continuation of the L2J lineage evolved, cleaned, simplified, benchmarked and rewritten across more than a decade. The project supports many clients spanning the Main, Classic and Essence lines, from C1 all the way to the latest updates.
Every chronicle ships as its own self-contained server distribution. There is no shared runtime library across eras. The trade-off is intentional: each game patch reshuffles classes, skills, packets and stats so deeply that forking per chronicle is cheaper than maintaining N feature flags. The pattern is consistent inside every folder, which is what this wiki documents.
If you only read one box on this page:
L2JMobius = a fleet of self-contained Lineage 2 server distributions, each split into a LoginServer + GameServer JVM, driven by XML content + SQL state + runtime-compiled scripts, with a uniform Handler / Manager / Data-loader / Network-packet layering inside every chronicle folder.
Where do I start?
Pick the door that matches what you came here for.
Installation
Step-by-step Windows walkthrough: JDK, Eclipse, XAMPP, clone the repo, run the Ant build, install the schema and launch both daemons.
Architecture
How the repo is laid out, how the LoginServer and GameServer hand a client off, how a packet becomes a damage number.
Patterns & Packages
The three patterns you'll see everywhere - Handlers, Managers, Scripts - and a tour of every top-level package in commons/ and gameserver/.
History & Legal
How a 2005 forum reject at L2jServer turned into L2JMobius, and the clean-room engineering foundation that keeps it legal.