#java
26 articles tagged java.
System Design: Building a Notification Service for 50 Million Users
A complete system design walkthrough — from blank page to production architecture — covering fan-out, multi-channel delivery, rate limiting, retry logic, and the trade-offs engineers get wrong in interviews and production.
The Modular Monolith: The Java Architecture Most Teams Should Be Using
A practical guide to the modular monolith in Java and Spring Boot — package structure, enforced module boundaries, domain events, and the honest case for why it beats microservices for most teams.
Designing the AI Request Pipeline: 8 Layers Between User Input and Your LLM
A production architecture blueprint for every layer between a user's message and a safe, reliable LLM response — with Spring Boot code you can actually use.
We Let Claude Code Refactor Our 200K-Line Java Monolith. Here's the Honest Result.
A real post-mortem on 6 weeks of AI-assisted refactoring — what it got right, what it silently broke, what we'd do differently, and the hybrid model we actually shipped.
Building AI Skills: GitHub Copilot Extensions, Claude Tools, and Reusable Agent Capabilities
One skill, three platforms. A complete guide to building a custom capability for GitHub Copilot, Claude, and your own AI agents — with real code, architecture diagrams, and a decision framework for when to use each.
AI Code Review at Scale: How We Use Claude to Review Every PR Before Humans See It
Six months, 4,200 pull requests, and a GitHub Actions workflow that catches real bugs before your team spends a single minute on review. The architecture, the prompt, the cost, and what we learned.
Feature Flags for AI: The Deployment Pattern That Saved Us From 3 Production Disasters
Why LLM features need flags more than anything else you've ever shipped — and the four flag patterns that let us swap models, A/B test prompts, and kill broken AI features in under 60 seconds.
10 Spring Boot Mistakes That Silently Kill Production Apps
A practical breakdown of the most common Spring Boot anti-patterns that cause degraded performance, memory leaks, and outages — with before/after code, real query plans, and how to catch them before they reach production.
Java Developer Roadmap 2026: What to Learn, What to Skip
A practical, opinionated roadmap for Java developers in 2026 — covering Java 21-24 features, Spring Boot 3, virtual threads, AI integration with Spring AI, cloud-native patterns, and what to stop wasting time on. Organized by experience level.
Your Spring Boot App Starts in 3 Seconds. With GraalVM Native, It's 80ms.
A practical, no-handwaving guide to compiling Spring Boot 3 apps to native executables — real benchmark numbers, common pitfalls, and when it's actually worth it.
Event-Driven AI: How Kafka Streams Changed the Way We Run LLMs in Production
From blocking HTTP calls to async event streams — the architecture shift that halved user-visible latency, eliminated 3AM pages, and lets us process 2M AI requests a day without hitting rate limit walls.
Temporal vs Spring Batch: Fixing Enterprise Java's Silent Job Failure Problem
Many enterprise Java teams have scheduled jobs failing silently, running concurrently, and corrupting data — without knowing. This guide explains how Temporal's durable execution model solves these problems, with complete code examples migrating from @Scheduled and Spring Batch.
We Replaced Spring WebFlux with Virtual Threads. Here's the Honest Result.
After 3 years of reactive streams in production, we migrated four services from WebFlux to Spring Boot + virtual threads. Code complexity halved, p99 latency dropped 34%, onboarding time for new engineers went from weeks to days. Here's exactly what we did — and what we kept reactive.
Structured Concurrency in Java 24: The Right Way to Manage Concurrent Tasks
Java 24 made Structured Concurrency GA. Here's what it is, why it matters alongside Virtual Threads, and how to use StructuredTaskScope to write safe, readable concurrent code.
Building a Spring Boot Microservices Project from Scratch (Complete Guide)
A complete walkthrough of building a production-ready microservices system with Spring Boot — covering service decomposition, API gateway, service discovery, Docker Compose, inter-service communication, and real code throughout.
Java 21 Virtual Threads: A Practical Guide for Spring Boot Developers
Virtual threads are Java 21's biggest performance upgrade in years — but most guides skip the real-world details. Here's what actually matters: when to use them, how they work with Spring Boot, common pitfalls, and benchmark data.
Microservices Done Right: Patterns I've Learned from 12 Years of Enterprise Architecture
Real-world patterns, anti-patterns, and hard lessons from designing and delivering microservices for global enterprises — from service decomposition to event-driven architecture to the observability you'll wish you had from day one.
Why Apigee is the Missing Layer in Every Microservices Architecture
After years of building enterprise microservices at scale — from Herbalife to HCA Healthcare — here's why I believe API management isn't optional anymore, and what Apigee-X brings to the table that raw gateways simply can't.
Spring Boot Complete Architecture Guide: From Foundation to Spring AI
A comprehensive end-to-end guide to Spring Boot architecture for experienced developers — IoC, AOP, security, data, resilience, testing, Spring AI, and production deployment — with diagrams and production-quality code throughout.
Spring Boot 3 New Features: What Every Java Developer Should Know
A practical tour of Spring Boot 3's biggest upgrades — native compilation with GraalVM, virtual threads, the Observability API, HTTP interface clients, and Problem Details — and when each actually matters.
Virtual Threads in Spring Boot: What Changes and How to Use Them
Java 21's virtual threads let Spring Boot handle massive concurrency for I/O-bound work without going reactive. How to enable them, when they help, and the pitfalls to avoid.
Modern Java for Backend Developers: The Features That Actually Matter
A practical tour of the modern Java features backend developers should be using now — virtual threads, pattern matching, records, sequenced collections — and why upgrading to a recent LTS pays off.
Spring AI vs LangChain4j: Which Should You Choose?
A practical, balanced comparison of Spring AI and LangChain4j for building LLM apps in Java — design philosophy, provider support, RAG, tools, and when to pick each.
How to Stream LLM Responses in Spring AI (Server-Sent Events)
Stream tokens as they're generated with Spring AI's ChatClient — a practical guide to SSE with WebFlux and Spring MVC, consuming the stream on the frontend, and handling errors in production.
Building a RAG Chatbot with Spring AI and PGVector
A step-by-step guide to a production-ready RAG chatbot in Java with Spring AI, PostgreSQL, and pgvector — ingestion, embeddings, retrieval, and grounded answers.
What's New in Modern Java — and How to Build AI With It
Modern Java (21→25) brings virtual threads, structured concurrency, records, and the FFM API. Here's what's new and how it powers AI apps.