- Docker – What It Is and Why It Exists
Start here. What a container actually is and how it differs from a virtual machine, the "works on my machine" problem it was built to solve, the difference between an image and a container, the exact versions this track is written against, the demo application every example is taken from, and the full lesson index in reading order.
- Spring Boot – Migrating from Spring, and from Boot 3 to 4
What XML configuration, a WAR file and a servlet container turn into once Boot is doing the work. Then the migration people actually face today: Boot 3 to Boot 4, where the modularised starters mean a dependency that used to bring autoconfiguration with it now silently brings none.
- React – Your First Component
A component is a function that returns markup — that is the whole idea. Naming and capitalisation rules React enforces, importing and exporting, why components must be declared at the top level, what "keeping a component pure" buys you, and an honest note on the class components you will still meet in older code.
- React Native – Set Up a Project with Expo
One command scaffolds the project. What `create-expo-app` generates and what each file is for, why `app.config.ts` beats a static `app.json` the moment you need an environment variable, path aliases that Metro reads straight from `tsconfig.json`, and the difference that trips everyone up — Expo Go versus a development build, and why anything with a native module needs the latter.
- Spring Boot – What It Actually Does
Starters, auto-configuration and the embedded server — the three things that separate Spring Boot from plain Spring. Why one dependency drags in twelve, how Boot decides which beans to create for you, and how to see every decision it made with the condition evaluation report.