The Facade pattern and the Adapter pattern are both structural design patterns in Java that are used to simplify and enhance the functionality of existing code. However, they have different intents and implementations.
The Facade pattern provides a simplified interface to a complex subsystem, making it easier to use and understand. It encapsulates the complexity of the subsystem behind a single interface, providing a high-level interface that clients can use to access the subsystem. The Facade pattern typically involves a facade class that provides a simplified interface to the subsystem, and a set of classes that implement the functionality of the subsystem.
The Adapter pattern, on the other hand, is used to make two incompatible interfaces work together. It converts the interface of one class into the interface that the client expects, allowing classes with incompatible interfaces to work together. The Adapter pattern typically involves an adapter class that adapts the interface of the adaptee class to the target interface that the client expects.
In summary, the main difference between the Facade pattern and the Adapter pattern in Java is that the Facade pattern provides a simplified interface to a complex subsystem, while the Adapter pattern adapts the interface of one class to another interface that the client expects.