Race Conditions & Concurrency“If two correct actions happen at the same time and the result is wrong — you have a race condition.”Today we move from duplicates (Day 2) to simultaneous execution, which is the #1 cause of “works in test, breaks in production”.1️⃣ What Is a Race Condi

Great — this is the right moment to learn idempotency, because it is one of the pillars of “code that doesn’t break”.I’ll explain it in three layers:Theory (mental model)Database-level design (most important)Spring Boot practical patternsNo shortcuts, no magic — just solid engineering.1�

This is a very important question.Most production bugs exist because developers don’t truly understand this.Let’s break it down slowly, clearly, and with real-world examples.1️⃣ What “Method Can Be Called Twice” REALLY MeansIt does NOT mean:You wrote method() twice in code ❌It DOES mea

? Day 1 — Why Software Systems Fail (and How to Think Like an Unbreakable Engineer)“Systems don’t fail because of bugs.They fail because engineers didn’t imagine the failure.”Today is about changing how you think, not writing code yet.If you get Day 1 right, the rest becomes natural.1️�

Introduction to Advanced Topics In this chapter, we'll cover some advanced topics in React, including:- Higher-Order Components (HOCs)- Render Props- Context API with Hooks- Server-Side Rendering (SSR)- Code SplittingHigher-Order Components (HOCs) A Higher-Order Component is a function tha

Introduction to Redux Redux is a state management library for JavaScript applications. It helps you manage global state by providing a single source of truth for state and a predictable, scalable way to update state.Core Concepts Redux has three core concepts:1. Store: The store is the cen

Introduction to React Router React Router is a popular library for managing client-side routing in React applications. It allows you to define routes for your application and navigate between them.Installing React Router To install React Router, run the following command in your terminal:n

Introduction to Context API The Context API is a way to share data between components in a React application without passing props down manually. It provides a way to share values between components without having to explicitly pass them down through props.Creating a Context To create a co