Pick the right persistent collection, and use transients only when profiling proves it helps.
Efficient Data Structures in Clojure focuses performance work on evidence rather than folklore. Java engineers should read these lessons as a disciplined JVM optimization path: measure, isolate the constraint, choose the smallest useful change, and preserve readability unless the metric proves the trade-off.
Use the child pages as practical checkpoints for reviewing hot paths, memory pressure, concurrency decisions, interop boundaries, and production feedback loops.