Build with Zero: six short lessons

Use ordinary Java to build something you can run, change and explain. This pack starts with the quiz already in Zero and uses the existing example shelf. You should know variables, if, methods and the idea of a class from beginning Java. Arrays and constructors are practised with worked examples here.

Lesson	Build and practise	Evidence to keep
1. Change the quiz	Fields, conditions and button events	Three answer checks and an explanation of the handler
2. Reuse an object	Constructors, methods and state versus display	Quiz and tracker results using one shared class
3. Grow a study session	Question objects, arrays and session state	A new question, complete run and restart
4. Animate an object	Coordinates, elapsed time and explicit updates	Comparison of following and jumping
5. Control movement	Conditions, direction and canvas bounds	Direction predictions and edge checks
6. Make a small improvement	Plan, implement, check and explain	A small working change with a test record

Work at your teacher's pace. Each of lessons 1–5 can fit a 45–60 minute class after setup; lesson 6 may need two classes. These are planning estimates, not classroom trial results. Teacher notes include prompts, likely mistakes, expected results and assessment guidance.

First complete the starter setup and run the default quiz. Local running does not need a GitHub account. Ask for help with first-time dependency downloads before starting the lesson clock.

When switching examples:

1. Stop the running app. Save your current Main.java and helper classes in a separate backup folder outside src/. A renamed Java file inside src/ can still compile and conflict with the next example.
2. Copy each lesson's listed files from examples/ into src/main/java/. Replace Main and the listed helpers. Keep src/main/java/zero/, pom.xml, zero.json, both wrappers and .mvn/. Do not copy a whole example folder into src/; use one Main at a time. Remove unused helpers only after backing them up.
3. Use Run App, or Ctrl+Shift+B on Windows/Linux and Command+Shift+B on macOS with the Zero extension installed. Without Zero, use Tasks: Run Task → Run App without Zero. Close or Stop the old app and run again after editing; a running window does not reload changes.
4. Run the unchanged example first, then make one change at a time. Click the canvas before testing keys in the animation and keyboard lessons.

The API reference explains Zero's methods. JavaFX controls keep their ordinary JavaFX names. Zero calls app lifecycle methods; your Main calls methods on your own objects explicitly.

For each lesson, write your prediction before running and record what actually happened. A useful check names the action, expected result and observed result. Keep the code and a few sentences explaining your change; screenshots can help show appearance but cannot explain the program on their own.

If your teacher asks for a repository link, follow the starter's GitHub and Pika instructions. Uploads default to simulation. Submit links separately in Pika; copying a link does not prove a real upload. Repository visibility and teacher access follow your teacher's instructions.