While the Façade pattern supports multiple purposes and has several variations, the fundamental implementation doesn't change: The Façade accepts a request, delegates the work to other services, ...

The Observable design pattern is found in many Java APIs and in reactive programming. Here's an introduction to the timeless Observable pattern in Java.

EJB Design Patterns goes beyond high-level design pattern descriptions into critical EJB-specific implementation issues, illustrated with source code implementations. The book contains a catalog of ...