Both the Builder pattern and the Abstract Factory pattern are creational design patterns in Java that allow for creating complex objects, but they differ in their intent and implementation.
The Builder pattern is used to construct objects that have a complex structure, where the construction process involves multiple steps and configurations. It separates the construction of an object from its representation, allowing for the creation of different variations of the same object. The Builder pattern typically involves a director, a builder interface, and concrete builder classes that implement the builder interface to construct the product.
On the other hand, the Abstract Factory pattern is used to create families of related objects without specifying their concrete classes. It provides an interface for creating objects in a particular family, where each concrete factory class implements the same interface but creates objects of different concrete classes. The Abstract Factory pattern typically involves an abstract factory interface, concrete factory classes that implement the factory interface to create related products, and abstract product interfaces and concrete product classes that implement the product interfaces.
In summary, the main difference between the Builder pattern and the Abstract Factory pattern in Java is that the Builder pattern is used to create complex objects with multiple steps and configurations, while the Abstract Factory pattern is used to create families of related objects without specifying their concrete classes.