STREAM API INTERVIEW QUESTION

1️⃣ The Master Stream Pattern (MOST IMPORTANT) Almost every Stream question follows this template: collection . stream () . intermediate_operation () . intermediate_operation () . terminal_operation (); Example numbers . stream () . filter ( n -> n % 2 == 0 ) . collect ( Collectors . toList ()); Flow Collection ↓ stream() ↓ Intermediate operations (filter / map / sorted / distinct) ↓ Terminal operation (collect / count / findFirst / forEach) This pipeline pattern repeats in almost every question . 2️⃣ Real Pattern Used in 90% Interview Questions You can categorize all questions into just 5 groups . 🧠 CATEGORY 1 — Filtering Pattern Used when question says: even numbers numbers > 5 remove duplicates starting with 1 positive numbers Pattern list . stream () . filter ( condition ) . collect (...) Example list . stream () . filter ( n -> n % 2 == 0 ) . collect ( Collectors . toList ()); Examples from PDF Even numbers Numbers >5 Starting with 1 Remove duplicates 🧠 CATEGORY 2 — Transformation