This repository demonstrates all 5 SOLID principles in Java with clean, easy-to-understand examples. These principles are the foundation of maintainable and scalable object-oriented design.
✅ Ideal for Java developers preparing for interviews or learning design patterns.
SOLID is an acronym representing 5 principles of object-oriented programming and design:
| Principle | Meaning |
|---|---|
| S - Single Responsibility Principle | A class should have only one reason to change |
| O - Open/Closed Principle | Software entities should be open for extension but closed for modification |
| L - Liskov Substitution Principle | Subtypes must be substitutable for their base types |
| I - Interface Segregation Principle | No client should be forced to depend on unused methods |
| D - Dependency Inversion Principle | Depend on abstractions, not concretions |
- Java 17
- Maven
- IntelliJ IDEA / VS Code
- JUnit (optional for testing)
Here are some excellent articles to deepen your understanding of the SOLID principles:
- Baeldung – SOLID Principles in Java
- Uncle Bob – Principles of Object-Oriented Design (Archived)
- DigitalOcean – SOLID: The First Five Principles of OOP
- Medium – SOLID Principles in Pictures
- freeCodeCamp – SOLID Principles Explained in Plain English
- JRebel – SOLID Principles in Java
- Medium – Mastering SOLID Principles (In-Depth Guide)