18 posts
I got curious about how Gmail checks email availability across billions of accounts in real time. Turns out the answer involves a data structure I'd only ever seen in textbooks.
Java arrays are fixed-size, indexed containers with O(1) random access. Full guide to declaring, iterating, copying, and searching them, plus the pitfalls that catch almost everyone.
Java's LinkedList is a doubly linked list that shines at insertions and deletions, but loses to ArrayList on almost everything else. Here's when it's the right call and when it's not.
RFC 10008 brings the HTTP QUERY method - safe, idempotent, and cacheable with a request body. After 20 years of POST /search hacks, here's what changes and how to use it.
BFS and DFS are the two fundamental graph traversal algorithms in Java. Here's how both work, when to pick each one, and the mistakes that'll bite you in interviews.
Dijkstra's algorithm finds the shortest path in a weighted graph. Here's how it works, a full Java implementation with PriorityQueue, and the one case where it breaks.
Every app that handles user uploads hits the same wall: how do you let people upload directly to cloud storage without exposing your credentials? Presigned URLs solve this, and Spring Boot makes it straightforward.
I chose the wrong message broker for a project once and spent months living with it. Here's how Kafka and RabbitMQ actually differ, and how to pick the one that won't make you regret it.
Got a dashboard where one slow API call makes the whole page feel sluggish? Here's how to use Suspense and useSuspenseQuery in TanStack Start so only the slow part shows a loading skeleton, everything else renders instantly.
Connecting Spring Boot to OpenAI's ChatGPT API using RestClient. I'll show you the setup, the DTOs, and the three lines of config I forgot and spent an hour debugging.
How I use Thymeleaf in Spring Boot for server-side rendering, from the first dependency to fragments and form binding, with the gotchas that aren't in the docs.
A full Splitwise LLD walkthrough for system design interviews, entity modeling, design patterns, the balance simplification algorithm, and a complete Java implementation you can run.
Wiring Google's Gemini API into a Spring Boot app using Spring AI. I'll walk through direct API setup, Vertex AI, function calling, multimodal processing, and the config gotchas that ate my afternoon.
You already know React and TypeScript, that's most of what you need to build native Android apps. Here's what actually changes when you move from the browser to a phone.
How to fetch data in React with useState and useEffect, the pattern I use for every project, the memory leak that taught me about AbortController, and when to reach for React Query instead.
I switched to Cloudflare's 1.1.1.1 after realizing my ISP was logging every site I visited. Here's how custom DNS works, why it matters, and how to set it up on any device.
Four hooks, zero fluff. A practical reference for the React hooks you'll actually use daily, with the gotchas that'll save you from bugs I've already hit.
I've shipped a lot of React code and made every hooks mistake in the book. Here's the practical guide I wish I had, five hooks, real examples, and the pitfalls that'll save you hours of debugging.