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 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.
