Object Oriented Programming using Java - Introduction to HashSets Part 1

00:00  Intro – What we’ll cover in this mini‑series on HashMaps 00:20  Why we need a quick refresher on ArrayLists first 00:48  Contiguous memory: definition & mental model 01:37  How an ArrayList grows and reallocates space 03:00  The hidden cost of contiguous reallocation 04:46  Fragmented (non‑contiguous) memory explained 05:32  Linked Lists: the classic fragmented data structure 07:55  Contiguous vs Fragmented – pros, cons, and big picture 08:20  Surprise: a HashMap blends both worlds (setup for next lecture) 09:00  Wrap‑up & what’s coming in Part 2 Welcome back to the Object‑Oriented Programming (Java) course! 📚 In this bite‑size lecture (Part 1 of our HashMap deep dive) we don’t touch code just yet—instead, we take a step back to understand the memory models that make HashMaps possible: Contiguous memory with ArrayList How the JVM doubles capacity and why it needs a new, adjacent block Fragmented (non‑contiguous) memory with Linked Lists Why nodes can live anywhere in RAM and link together with pointers Performance trade‑offs between the two approaches A teaser of how HashMaps cleverly combine both to get O(1) average look‑ups By the end, you’ll see why HashMaps are designed the way they are—and you’ll be ready for Part 2, where we build and analyze a HashMap in Java. 🔔 New here? Subscribe and turn on notifications so you don’t miss the next lecture! 📂 Course Playlist ▪️ Full OOP in Java playlist 💬 Questions? Drop them in the comments. I try to answer every one! #Java #DataStructures #HashMap #ArrayList #LinkedList #ComputerScience