Deep Dive-Java Collections& Internal: ArrayList, Set, HashMap ConcurrentHashMapCopyOnWrite(Interview

Deep Dive — Java Collections & Internals: ArrayList, Set, HashMap, ConcurrentHashMap, CopyOnWrite (Interview Prep) Java Collections Explained: Array vs Collection, HashMap Internals, Fail-Fast vs Fail-Safe (0 → 5+ yrs) HashMap, ArrayList, ConcurrentHashMap — Internal Working + Interview Questions (Java) Java Collections — Full in-depth explainer for beginners to 5+yrs | HashMap internals, ArrayList vs LinkedList, ConcurrentHashMap, CopyOnWrite & Interview Prep In this single video I explain the Java Collections framework end-to-end: • Array vs Collection • List: ArrayList, LinkedList, Vector (internal structure, complexity, when to use) • Set: HashSet, LinkedHashSet, TreeSet • Map: HashMap internals (table, buckets, hash, loadFactor, resizing, treeify) • Concurrent collections: ConcurrentHashMap (Java 7 vs Java 8+), CopyOnWriteArrayList/Set • Synchronization models: synchronized/Vector vs segment locking vs bucket/bin locking vs CAS • Fail-fast vs Fail-safe, ConcurrentModificationException • How to tune defaults: initialCapacity, loadFactor, (concurrencyLevel for older CHM overloads) • Interview questions & common pitfalls 🔔 Subscribe for more: @anubhavitech Chapters (add actual timestamps in YouTube after uploading) 0:00 Intro & What I cover 0:45 Array vs Collection — conceptual differences 3:30 List overview & Big-O (ArrayList vs LinkedList vs Vector) 8:40 ArrayList internals — backing array, growth, complexity 14:20 LinkedList internals — nodes, pointer ops, when to use 17:50 Vector & Hashtable — legacy, synchronization notes 20:30 Set types — HashSet/LinkedHashSet/TreeSet 24:10 HashMap internals (Java 8+): table, bucket, hash, index calc 30:45 Resize & loadFactor — why 0.75 is default 36:55 Fail-fast iterators vs fail-safe (CopyOnWrite) & CME 40:30 CopyOnWriteArrayList/Set — how they work & tradeoffs 43:20 ConcurrentHashMap — segment locking (older) vs bin/CAS approach (Java 8+) 49:30 Tuning concurrency/initialCapacity/loadFactor (practical tips) 53:00 Common interview Qs & quick answers 58:45 Summary & next steps Resources & code (add your links) • Code snippets / Gist: [https://gist.github.com/123-anubhav/277b7909976dc3186f2fab0fefa7afd4] If this video helped you — like 👍, subscribe 🔔 and comment below what topic you want next (e.g., HashMap resizing animation, TreeMap internals, or custom hash functions). Follow me: YouTube: @anubhavitech GitHub: [https://github.com/123-anubhav] #Hashtags #Java #JavaCollections #InterviewPrep