Kafka's UNKNOWN_PRODUCER_ID and OutOfOrderSequenceException: Why Your Idempotent Producer Fails After a Restart
A deep dive into why idempotent Kafka producers throw UNKNOWN_PRODUCER_ID and OutOfOrderSequenceException in production, how broker-side producer state expiry causes it, and how to fix it with KIP-360 semantics and proper client configuration.
HikariPool-1 - Connection is not available, request timed out after 30000ms: Diagnosing and Fixing Connection Pool Exhaustion in Spring Boot
A production-grade breakdown of the HikariCP Connection is not available timeout in Spring Boot β why it happens under load, how to reproduce it locally, and how to fix and prevent pool exhaustion for good.
Consumer Rebalance Storms: Why Your Kafka Consumer Group Never Stabilizes
A deep dive into Kafka consumer rebalance storms β the exact CommitFailedException and JoinGroup log spam that signals it, why max.poll.interval.ms and eager rebalancing are usually to blame, and how to fix it with cooperative sticky assignment and static membership.
LazyInitializationException: could not initialize proxy β no Session β Root Cause and Fix
A deep dive into Spring Boot's LazyInitializationException, why it slips past code review and blows up in production, and how to fix it properly instead of slapping @Transactional on everything.
Educative.io Review in 2026: Is It Worth It for Developers?
Thinking about Educative.io? Here's the honest verdict: outstanding for interview prep and system design, not ideal for beginners. Full review with pricing, comparisons, and FAQ.
5 Steps to Ace Your FAANG Interview: Checklists for DSA, LLD & HLD
Stop grinding blindly. Follow this structured 5-phase checklist to master Data Structures, Low-Level Design, System Architecture, and behavioral questions for major tech company interviews.
Mastering Spring Boot: Building Production-Ready Microservices
Spring Boot has revolutionized Java application development by eliminating boilerplate configuration and providing a streamlined approach to building production-ready applications. In this comprehensive guide, we'll explore advanced Spring Boot concepts and patterns that will help you build robust, scalable microservices that can handle real-world demands. Understanding
Spring Boot Hello World Tutorial with Lombok and H2 Database β Quick Start for Beginners
Learn how to create a Hello World Spring Boot application using Lombok for cleaner code and the H2 in-memory database for rapid development. This step-by-step guide includes annotations, project setup, REST API, H2 console access, and more to kickstart your Spring Boot journey.
How to fix port 8080 already in use error on Windows and macOS
Getting the βWeb server failed to start. Port 8080 was already in useβ error? Learn how to identify and kill the process blocking port 8080 on Windows and macOS using simple terminal commands. Fix server startup issues fast and keep your development running smoothly.
Spring vs. Spring Boot: Key Differences Developers Must Know
Spring or Spring Boot? One gives you full control, the other gets you up and running fast. If you're building Java apps, knowing the difference isn't optionalβitβs critical. Hereβs the breakdown every dev should read.
