Hi everyone, I’ve been developing Janice, a high-performance asynchronous file synchronization tool built from the ground up to solve a very specific bottleneck: the massive overhead when syncing directories with hundreds of thousands of files. The Problem & The Goal: Traditional tools like rsync are fantastic, but they often choke on file traversal during incremental syncs. My primary engineering goal for this project was to ensure it can process TB-level data at full disk rate without the CPU or thread management becoming the bottleneck. The Architecture: To achieve this, I abandoned traditional threading models. Janice leverages Kotlin Coroutines alongside Java NIO's asynchronous file and networking capabilities. By utilizing purely async I/O, it pushes the limits of what the modern JVM can do with massive concurrency.…