Design Patterns · Module 3 of 10

Builder and Prototype

Create complex objects step by step or by cloning.

📖 Key ideas

Builder constructs complex objects step by step: new Pizza.Builder().size("L").cheese().build().
Avoids constructors with many parameters.
Prototype creates new objects by copying an existing one.
Shallow vs deep copy matters when cloning.
Builders improve readability and immutability.

💡 Real-life example: Builder is ordering a custom sandwich item by item; Prototype is photocopying a filled form and editing it.

BuilderStep-by-step object construction

PrototypeCreating by cloning

Telescoping constructorMany overloaded constructors

Deep copyCopies nested objects too