- Spring Boot – Building a REST API
@RestController end to end: path and query binding, request bodies, Bean Validation, and returning the right status code instead of 200 for everything. Why the pizza API exposes a UUID rather than its primary key, and why a DTO is not ceremony once an entity has a password field on it.
- Python – Get Started
Start here. Install Python, run your first script, and understand the difference between the REPL and a file. Which Python version this track uses and why, every major 3.x release and what each one added, virtual environments and pip, and the map of the other 25 posts with the order to read them in.
- Java Interface
An interface is a contract: a list of methods a class promises to provide, with no state and (mostly) no implementation. It is the main tool Java gives you for writing code that does not depend on a specific class — and that is what makes code testable and changeable. Declaring and implementing one…
- Angular – Component Styles, Sass and Bootstrap
Angular scopes a component's styles to that component by default, which changes how you think about CSS. View encapsulation and the attribute selectors it emits, `:host` and `:host-context`, `[class]` and `[style]` bindings, and layering Sass overrides on Bootstrap in `angular.json` so they win without a single `!important`.
- Docker – Layer Caching and Build Speed
One rule explains most fast Dockerfiles: copy the dependency manifest and install dependencies *before* copying your source. How the cache is keyed, why one changed line can invalidate every layer after it, the `pom.xml`-first and `package.json`-first patterns, and BuildKit cache mounts.