Quelles sont les heures d'ouverture ?

Lundi 09:00 - 17:00 Mardi 09:00 - 17:00 Mercredi 09:00 - 17:00 Jeudi 09:00 - 17:00 Vendredi 09:00 - 17:00 Samedi 09:00 - 17:00

The Dev World - by Sergio Lema

Page d'Accueil
France
Paris
The Dev World - by Sergio Lema

Are you ready for a Dev Challenge? Welcome to The Dev World.

Professional developer since 2008, I'll share my knowledge with games and videos about the technologies I master: Java, databases, DevOps tools and more.

03/08/2026

Stop Being an AI Babysitter: How to Use LLMs Without Losing Code Ownership

Most developers use AI as a shortcut, not as a tool. The result is code they can't explain, can't test, and can't debug — until it takes down production on a Friday. Moving from coder to architect means applying a Zero-Trust Policy to every line of AI-generated code, breaking problems into typed contracts, and directing the model rather than accepting whatever it offers first....

Most developers use AI as a shortcut, not as a tool. The result is code they can’t explain, can’t test, and can’t debug — until it takes down production on a Friday. Moving from c…

27/07/2026

Centralizing Pricing Logic: Stop Scattering Your Business Rules

I've chased enough one-cent bugs to know the pattern: a rounding function in the frontend, a currency conversion in the backend, a separate calculation in the invoice job — each slightly different. When a customer disputes a charge, you can't reconstruct what happened. Here's why your backend must be the sole pricing authority, and how to build it that way....

I’ve chased enough one-cent bugs to know the pattern: a rounding function in the frontend, a currency conversion in the backend, a separate calculation in the invoice job — each slightly diff…

20/07/2026

Why AI Won’t Replace Developers Who Lead the Tool

I use AI code assistants every single day. My net output hasn't changed. Not because the tools are overhyped — but because most developers are using them wrong. If you can't explain the code an AI gave you, you didn't write it. You just hosted it. Here's how to stay the architect, not become the prompt....

I use AI code assistants every single day. My net output hasn’t changed. Not because the tools are overhyped — but because most developers are using them wrong. If you can’t explain the…

13/07/2026

Modern State Management in React: Stop Using Redux for Server Data

I've seen teams spend months building custom caching layers on top of Redux, essentially re-inventing a database in the browser. The real problem isn't which state library to use — it's that server state and UI state are fundamentally different concerns that require different tools. This post covers TanStack Query, Spring Data Projections, optimistic updates, and why simplicity always wins....

I’ve seen teams spend months building custom caching layers on top of Redux, essentially re-inventing a database in the browser. The real problem isn’t which state library to use — it& #…

06/07/2026

Structured Logging in Java Microservices: SLF4J, MDC, and Distributed Tracing in Practice

I have spent more hours than I care to admit staring at logs that said "Process started" followed immediately by "Error: null." A logging strategy is not about making your console look active — it is a forensic requirement for production survival. If your logs don't provide a clear path to the root cause of a failure, they are just expensive noise....

I have spent more hours than I care to admit staring at logs that said “Process started” followed immediately by “Error: null.” A logging strategy is not about making your c…

29/06/2026

Why I Stopped Calling Myself a Full-Stack Developer

The term "Full-Stack Developer" has become a catch-all that often masks the true value of an experienced engineer. After 20 years in the industry, I’ve realized that my value doesn't come from knowing how to write a useEffect in React or a Stream in Java. My actual role is that of a Feature Expert — and languages and frameworks are merely implementation details....

The term “Full-Stack Developer” has become a catch-all that often masks the true value of an experienced engineer. After 20 years in the industry, I’ve realized that my value doesn& #821…

22/06/2026

The Saga Pattern: Managing Distributed Transactions Without Losing Your Mind

Imagine it's Friday. 4:15 PM. You've just deployed the new "Order-to-Delivery" microservice flow. Service A calls Service B, B calls C. It's elegant. It's "decoupled." You go home and feel like a cloud-native architect. Then, at 2 AM, the pager goes off. A customer bought a $2,000 espresso machine. Service A created the record. Service B charged the card. But Service C was having a moment because someone ran a backup during peak hours — and the inventory update failed. The customer has no espresso machine, you have their $2,000, and your Order service thinks everything is fine....

Imagine it’s Friday. 4:15 PM. You’ve just deployed the new “Order-to-Delivery” microservice flow. Service A calls Service B, B calls C. It’s elegant. It’s & #8220…

15/06/2026

Why AI is Replacing Junior Developers and How Mid-Level Engineers Can Survive

Many junior developers struggle to find jobs as AI handles basic tasks efficiently. However, companies now seek senior engineers to rectify poor AI-generated code. Developers should use AI for problem-solving rather than for coding directly, ensuring they understand and own their work to effectively address future issues and enhance system design....

Many junior developers struggle to find jobs as AI handles basic tasks efficiently. However, companies now seek senior engineers to rectify poor AI-generated code. Developers should use AI for prob…

08/06/2026

Choosing the Right AI Coding Agent: Claude Code vs. GitHub Copilot vs. Gemini Code Assist

The AI coding tools market has evolved towards agentic workflows. Claude Code excels in complex engineering tasks like multi-file refactoring but has high token consumption. GitHub Copilot is ideal for low-latency, single-file autocomplete, while Gemini Code Assist effectively handles long-context tasks and large repositories without forceful edits. Proper tool selection is crucial....

The AI coding tools market has evolved towards agentic workflows. Claude Code excels in complex engineering tasks like multi-file refactoring but has high token consumption. GitHub Copilot is ideal…

01/06/2026

Why You Should Never Use Floating Point for Money

The floating-point arithmetic are inadequate for financial systems, advocating for the use of BigDecimal to ensure precision and avoid rounding errors. Key principles include domain isolation, stringent data types, and thorough edge-case testing. Proper implementation is crucial for maintaining price integrity and avoiding financial discrepancies....

The floating-point arithmetic are inadequate for financial systems, advocating for the use of BigDecimal to ensure precision and avoid rounding errors. Key principles include domain isolation, stri…

Adresse

Paris

Heures d'ouverture

Lundi	09:00 - 17:00
Mardi	09:00 - 17:00
Mercredi	09:00 - 17:00
Jeudi	09:00 - 17:00
Vendredi	09:00 - 17:00
Samedi	09:00 - 17:00

Site Web

https://sergiolema.dev/

Notifications

Soyez le premier à savoir et laissez-nous vous envoyer un courriel lorsque The Dev World - by Sergio Lema publie des nouvelles et des promotions. Votre adresse e-mail ne sera pas utilisée à d'autres fins, et vous pouvez vous désabonner à tout moment.