This repository contains a web-based, interactive introduction to LiquidJava. The tutorial has four short examples:

1. RGB value refinements;
2. Midpoint method contracts;
3. External socket state refinements;
4. Stack ghost variables.

Learners can edit Java snippets, run lightweight in-browser checks, answer quick knowledge questions, and move freely between sections. The tutorial does not collect, persist, or export user data.

Run the local development server:

npm run dev

Then open http://localhost:8000.

All tutorial content is in tutorial-data.js. The interface renders the lessons from that single configuration object. Reusable exercise checks are centralized in validation-regexes.js.

Each lesson contains:

• Explanatory copy and a read-only example;
• Starter and solution code;
• Regular-expression checks for the coding task;
• Automatically checked multiple-choice and short-answer questions.

Add, remove, or reorder lesson objects to change the tutorial without editing app.js or index.html.

The browser checker is intentionally lightweight: it recognizes the requested annotations and values but does not run the LiquidJava compiler. Use the LiquidJava VS Code extension for real verification tasks.