Explain the Factory pattern and its variations.

Factory patterns encapsulate object creation. Simple Factory: static method creates objects (not a GoF pattern). Factory Method: subclasses decide which class to instantiate. Abstract Factory: creates families of related objects without specifying classes. Benefits: decouples client from concrete classes, follows Open/Closed principle, supports dependency injection. Use when: object creation is complex, type determined at runtime, hiding implementation details. Common in frameworks for creating service instances.