Micro-topic BB2_L21_M1 — Stream pipeline mindset: build → then execute
Goal: You can explain streams as “what I want” pipelines, and you can predict when work actually happens.
Micro-topic BB2_L21_M2 — Transformations: filter, map, flatMap, distinct, sorted, limit
Goal: You can transform collections with stream operations correctly (and avoid common traps).
Micro-topic BB2_L21_M3 — Collectors: toList, toSet, toMap, groupingBy, joining
Goal: You can produce Lists/Sets/Maps from streams and handle the top collector pitfalls (duplicates, order, mutability).
Micro-topic BB2_L21_M4 — Optional: disciplined “no result” without null chaos
Goal: You can use Optional as a return-type weapon and avoid the classic Optional misuse patterns.
Micro-topic BB2_L21_M5 — Streams + Optionals together: findFirst, Optional.stream, and clean “search then act”
Goal: You can combine streams and optionals without messy nested logic.