Java platform, Enterprise Edition

Java Platform, Enterprise Edition (Java EE), is an open, community-driven standard for building enterprise applications.

Java EE technologies are well-suited for creating microservices, especially Java API for RESTful Web Services (JAX-RS), and Contexts and Dependency Injection for Java EE (CDI). Annotations are used for both specifications, with support for dependency injection, light-weight protocols and asynchronous interaction patterns. Concurrency utilities in Java EE7 further provide a straight-forward mechanism for using reactive libraries like RxJava2 in a container-friendly way.

Modern Java EE application servers (WebSphere Liberty, Wildfly, TomEE, Payara) undercut claims of agonizingly painful dealings with application servers. All of these servers can produce immutable, self-contained, lightweight artifacts in an automated build without requiring additional deployment steps. Further, composable servers like WebSphere Liberty allow for explicit declaration of spec-level dependencies, allowing the runtime to be upgraded without creating compatibility issues with the application.

Applications using a reduced set of Java EE technologies and packaged with application servers like WebSphere Liberty that tailor the runtime to the needs of the application result in very clean applications that can move between environments without requiring code changes, mock services, or custom test harnesses.

The examples in this book will primarily use Java EE technologies like JAX-RS, CDI, and JPA. These specifications are easy to use, and are broadly supported without relying on vendor-specific approaches.