- Java OOP
Object-oriented programming is four ideas. Most explanations define them; this post shows each one in code and says what it is actually for — because the fourth idea, inheritance, is the one beginners reach for constantly and professionals reach for rarely. 1. Encapsulation — hide the data, expose…
- Spring Boot – Spring Web MVC
How a request actually reaches your method: DispatcherServlet, handler mapping, argument resolvers and message converters. Where CORS is configured and why it has to agree with the security filter chain, and what Boot 4's webmvc starter gives you before you write a line.
- Java Class
A class is a blueprint. It says what data an object holds and what it can do, and then you create objects from it. Every line of Java you have written so far lived inside one. Fields, constructor, methods Note that the class holds the data and the rules about that data together. The check in…
- React Native – Lists with FlatList
`ScrollView` renders every child immediately and holds them all in memory. `FlatList` virtualises — and on a phone that is the difference between a list that opens and one that hangs. `keyExtractor`, `renderItem`, header and empty components, multi-column grids, pull-to-refresh in two props, and why `numColumns` needs a `key` to change.
- Java Method
A method is a named block of code that takes inputs and optionally produces a result. Methods are how you stop repeating yourself and how you break a large problem into pieces small enough to understand one at a time. Anatomy public — who can call it. Packages covers the four options. int — the…