Programming Concepts & Tutorials
In-depth articles on Java internals, Spring Boot, Laravel, and clean code practices. Learn by building.
HashMap Internal Working in Java — Deep Visual Guide
How does HashMap actually store and retrieve data? We walk through the Node[] table, hash() spread function, bucket index calculation (n-1) & hash, collision chaining, treeification at 8 nodes, and resize at 0.75 load factor — with a live interactive 16-bucket visualizer.
HashMap Internal Working in Java — Deep Visual Guide
How does HashMap actually store and retrieve data? We walk through the Node[] table, hash() spread function, bucket index calculation (n-1) & hash, collision chaining, treeification at 8 nodes, and resize at 0.75 load factor — with a live interactive 16-bucket visualizer.
SQL Interview Queries Practice Guide - Employee Questions, Joins, and 100+ Challenges
A practical guide to practicing SQL interview queries using employee tables, join questions, blog analytics, and a workshop packed with 100+ runnable prompts.
Java equals() and hashCode() Contract — The Complete Visual Guide
Understanding why HashMap behaves differently when you override hashCode() and equals() — with 5 interactive scenarios that show exactly what happens inside the bucket chain.
Java Object Cloning: Shallow vs Deep — A Visual Guide
When you clone an object in Java, do you get a truly independent copy — or a ghost that still shares memory with the original? Understand shallow vs deep cloning with step-by-step heap memory diagrams.
Java Executor Framework: From Executor to ForkJoinPool — Complete Visual Guide
Master Java's Executor hierarchy with an interactive thread pool simulator, live task animations, and deep walkthroughs of every type — from the root Executor interface to ForkJoinPool and Spring's ThreadPoolTaskExecutor.
Java Memory Architecture & Garbage Collection — A Complete Visual Guide
Every Java object is born in Eden, might survive to Old Gen, and is eventually collected. Walk through every JVM memory region, every GC generation, and every major algorithm — with live simulations.