The Director defines the construction process, while the Builder handles the steps.

Builder always subclasses Director.

The Builder defines construction rules, while Director implements them.

They are interchangeable roles.

Abstract Factory.

Adapter.

Singleton Factory.

Parametrized Factory Method.

It ensures only one instance of a class is created.

none

It adapts one interface to another.

It provides an interface to a family of related algorithms.

It separates construction of a complex object from its representation.

Builder focuses on step-by-step object construction, Abstract Factory focuses on product families.

Builder is for families, Abstract Factory is for step-by-step construction.

Both solve the same problem.

Neither uses polymorphism.

Avoids creating new classes.

Ensures compatibility among products of the same family.

Guarantees immutability.

Allows dynamic runtime selection of unrelated products.

It helps integrate legacy code.

It enforces product family consistency.

It can use class inheritance.

It can use object composition.

Prevents interface evolution.

May add unnecessary complexity if used excessively.

Breaks Open/Closed principle.

Forces tight coupling.

Switching between multiple families of related objects.

Constructing objects with many optional parameters.

To separate abstraction from implementation.

When multiple adapters are required.

Builder (both create objects step by step).

Adapter (both involve two interfaces but differ in intent).

Decorator (both add functionality).

Factory (both manage product families).