Java
equals() and hashCode() in Java: Comparing Objects Correctly
Learn how equals() and hashCode() really work in Java, why you must override them together, and how they affect HashMap and HashSet — with clear beginner examples.
System Design › Start Here
Latency, Throughput & Availability: How We Measure Fast and Reliable
Latency, throughput and availability explained from scratch — what each measures, the highway analogy, why averages lie (p50 vs p99 tail latency), the availability nines table, and how these numbers drive every architecture decision.
Java
Enums and Wrapper Classes in Java Explained
Learn Java enums and wrapper classes — use enums for a fixed set of safe values, understand Integer/Double wrappers, autoboxing, and handy methods like parseInt.
System Design › Start Here
Client, Server, Database & API: The 4 Words That Explain All Software
The four words behind every app — client, server, database and API — explained from zero with restaurant analogies, real API endpoints, JSON, and how they all talk to each other. The mental model that makes system design click.
Java
Generics in Java: Type-Safe Code Explained for Beginners
Learn generics in Java — what the angle brackets mean, why they make collections type-safe, and how to write your own generic class, all with clear examples.
Java
List, Set and Map in Java: How to Use Each (with Examples)
A hands-on guide to Java List, Set and Map — ArrayList, HashSet, and HashMap with real examples, and a simple decision guide for which one to use when.
System Design › Start Here
How the Web Works: What Really Happens When You Type a URL
A beginner's tour of how the web works — DNS, IP addresses, TCP, HTTPS, HTTP requests and responses, status codes, and the full client-server round trip. The foundation for all of system design, in plain English.
System Design › Start Here
What Is System Design? A Beginner's Guide (Plain English, Real Examples)
System design made simple. Learn what a 'system' really is, what happens when you open a website, functional vs non-functional requirements, HLD vs LLD, and how to actually start learning — in plain English with real examples and diagrams.
Java
The Java Collections Framework: List, Set and Map Overview
A beginner map of the Java Collections Framework — why collections beat arrays, and the three core types List, Set and Map, with a first taste of ArrayList.
Java
Exception Handling in Java: try, catch, finally and throw Explained
Learn exception handling in Java — try, catch, finally, common exceptions like NullPointerException, checked vs unchecked, and throwing your own, all beginner-friendly.
Education
CBSE Class 12 Commerce Sample Papers 2026-27: Download PDF, Exam Pattern & Marking Scheme
Download CBSE Class 12 Commerce Sample Papers 2026-27 PDF for Accountancy, Business Studies, Economics & English with official marking scheme, exam pattern and prep tips.
System Design › Low-Level Design
How to Approach a Low-Level Design (LLD) Interview: The Framework
A repeatable framework for LLD and machine-coding rounds: clarify requirements, find the objects, define relationships (has-a vs is-a), apply design patterns where they fit, sketch the class diagram, then write clean SOLID code. With a worked parking-lot example in Java.