Java in IntelliJ IDEA: Learn by working with Real Code

You will work inside ShopFlow, a small checkout and order-processing project.

So instead of writing random Java snippets from scratch, you will do what developers actually do most of the time.

You will read existing code.

Follow tests.

Debug wrong values.

Fix business logic.

Add small features.

Refactor code without breaking what already works.

The project is built around products, cart items, customers, coupons, shipping, orders, and totals. Simple domain. Realistic problems.

You will work through tasks that look like normal developer work: bug reports, feature requests, cleanup tasks, and final verification.

You will fix cart total calculations, validate customer data, repair discount logic, connect checkout to the correct pricing rules, add percentage coupons, implement free shipping, clean up duplicated code, improve naming, and add loyalty tiers.

You will also use IntelliJ IDEA as part of the workflow, not just as a place to type code.

You will navigate the project, jump to declarations, find usages, run focused tests, use the debugger, inspect values, and use refactoring tools instead of manually digging through files.

This course is best for learners who already know basic Java syntax, but do not yet feel confident inside an existing Java project.

By the end, you will have practiced the real rhythm of Java maintenance:

find the rule, understand the code, make the change, and prove it with tests.