Low-Level Design
System Design › Low-Level DesignBuilder Pattern in Java (with Example)
The Builder pattern explained: construct an object with many optional fields step by step via a fluent chain and build(), avoiding telescoping constructors and getting an immutable result. Java code, UML, when to use.
System Design › Low-Level DesignAbstract Factory Pattern in Java (with Example)
The Abstract Factory pattern explained: a factory of factories that creates whole families of related objects (a matching button + checkbox) consistently. Java code, UML, and Factory Method vs Abstract Factory.
System Design › Low-Level DesignFactory Method Pattern in Java (with Example)
The Factory Method pattern explained: centralise object creation behind a method that returns an interface, so adding a new type never touches the client. Java code, UML, Open/Closed, and when to use it.
System Design › Low-Level DesignSingleton Pattern in Java (with Thread Safety)
The Singleton pattern explained: private constructor + static getInstance, the thread-safety trap, and the fixes (eager init, double-checked locking, enum). With Java code, UML, and when not to use it.
System Design › Low-Level DesignDesign Patterns in Java: The Complete Guide
Your map to design patterns: what they are, the three families (creational, structural, behavioral), when to use each, and links to a deep-dive on all the most-asked patterns — with Java examples and UML.
System Design › Low-Level DesignUML Class Diagrams for LLD Interviews (Quick Guide)
Just enough UML to ace a low-level design interview: the class box, the relationship arrows (inheritance, realization, composition, aggregation, association), and multiplicity — with a worked example.
System Design › Low-Level DesignSOLID Principles Explained (with Simple Examples)
The five SOLID principles made simple — Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion — each with a plain example and why it makes code extensible and testable.
System Design › Low-Level DesignObject-Oriented Design Basics for LLD Interviews
The OOD foundation every low-level design interview needs: the four pillars of OOP, object relationships (association, aggregation, composition, inheritance), and why to favour composition over inheritance.
System Design › Low-Level DesignHow 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.