Design Patterns
Design patterns are reusable solutions to recurring object-oriented design problems. The Gang of Four (GoF) patterns — creational, structural, and behavioral — appear everywhere in Java frameworks and are a staple of senior-level interviews. Spring itself is an application of Factory, Proxy, Template Method, and Observer patterns.
What You'll Find Here
Notes are being added. Planned topics:
| Topic | Description |
|---|---|
| Creational Patterns | Singleton, Builder, Factory Method, Abstract Factory, Prototype. |
| Structural Patterns | Decorator, Adapter, Facade, Composite, Proxy. |
| Behavioral Patterns | Strategy, Observer, Command, Template Method, Chain of Responsibility, State. |
Learning Path
- Creational Patterns — start with Singleton (thread-safe idioms), Builder (used everywhere with
@Builder), and Factory. - Structural Patterns — Decorator (Java I/O streams) and Proxy (Spring AOP) are the most Java-relevant.
- Behavioral Patterns — Strategy (replaces
if/elsechains), Observer (Spring events), and Template Method (Spring'sJdbcTemplate) are must-knows.
Related Domains
- Object-Oriented Programming — design patterns are OOP in action; solid OOP knowledge is a prerequisite.
- Spring Framework — Spring's internals implement Factory, Proxy, Template Method, and Observer.
- System Design — design patterns at the class level support the architectural patterns at the system level.