Author: Sergio Lema
-
Event-Driven Architecture with Spring Boot and AWS EventBridge: Escaping the Distributed Monolith
Most microservice migrations just trade a local monolith for a distributed one. This post covers how to implement Event-Driven Architecture with Spring Boot and AWS EventBridge — from choreography patterns and schema contracts to idempotency and distributed tracing.
-
Google Cloud Run Limitations: When Serverless Complexity Outweighs the Cost Savings
Google Cloud Run is a great fit for simple APIs, but once you need large file uploads, high availability, and event-driven reliability, the workarounds pile up fast. This post walks through the real cost of fighting Cloud Run’s constraints and when GKE Autopilot or Compute Engine becomes the more honest choice.
-
The Command Pattern in Java: Eliminating Fat Service Classes with Commands and Handlers
Fat Service classes are a liability — one class that does everything is a class that’s impossible to test and dangerous to change. This post shows how to apply the Command pattern in Java using Records, Repository interfaces, and single-responsibility Handlers to keep your business logic clean and isolated.
-
Spring Security 6 OAuth 2.1: Replacing Implicit Grant and ROPC with PKCE
If your Spring Security config still uses the Implicit Grant or Resource Owner Password flow, you’re running on borrowed time. This post breaks down why OAuth 2.1 makes PKCE mandatory, kills legacy flows, and shows the exact config difference between a legacy setup and a production-hardened one.
-
Why JavaScript Floating Point Math Breaks Your App (And How to Fix It)
JavaScript’s IEEE 754 floating point format means 0.1 + 0.2 !== 0.3 — and that’s just the obvious case. This post covers why it happens, where it silently breaks production code, and four concrete strategies: toFixed for display, integer arithmetic for money, a scale-round-ceil pattern for computed floats, and decimal.js for complex chains.
-
Fullstack 2026: Building the Modern Spring Boot 3.4 and React 19 Architecture
After 15 years in the industry, the author emphasizes the need for simplicity in development. The post discusses using Spring Boot 3.4 and React 19 to streamline setups by eliminating boilerplate, automating infrastructure, and enhancing developer experience. Key strategies include Docker integration, virtual threads, and proxy configurations for efficient development.
-
The JVM Stack: A Developer’s Quick Guide
This content explains the difference between stack and heap memory in Java, highlighting their roles in memory allocation. The stack is thread-specific, efficient, and short-lived, while the heap is shared across threads and managed by the Garbage Collector. Understanding these concepts helps prevent common errors like StackOverflowError and OutOfMemoryError.
-
Choosing a Deployment Strategy: A Developer’s Guide to Canary, Blue-Green, and Rolling Updates
Effective deployment strategies are crucial for developers post-code commit. Blue-Green, Canary, and Rolling Updates cater to different needs, balancing factors like cost, risk, and release frequency. Understanding these strategies helps ensure smooth transitions without downtime, optimizing user experience while managing potential issues and resource allocation.
-
Google Sign-In for React Native: The Complete Setup Guide That Actually Works
Integrating Google Sign-In in a React Native app involves configuring Firebase and Google Cloud Console, managing SHA-1 fingerprints, and using the @react-native-google-signin library. Common issues arise post-deployment due to silent failures linked to mismatched fingerprints, emphasizing the need for accurate configuration across environments. Proper setup is crucial for a smooth user experience.
-
Spring @Transactional is Not Magic: The Proxy Trap and Why Your Data Isn’t Safe
**Most developers treat @Transactional like a magic wand, but it is actually a proxy-based abstraction that is remarkably easy to break.** If you do not understand Java AOP, you are likely creating “zombie data” and performance bottlenecks without even knowing it. This post deconstructs the **self-invocation trap**, the **rollback myth of checked exceptions**, and why…
The Dev World - Sergio Lema 