In this section, we're going to take a look at the different APIs of Java EE 8 and the latest advances, with a focus on the more microservice-relevant APIs. We're going to look at JSR 370, which is JAX-RS 2.1; JSR 367, which is the JSON Binding; and also JSR 374, which is the Java API for JSON Processing.
We saw the different APIs in Java EE 8 in the Overview of Java EE 8 section. The ones in blue are the ones that have been added or revamped. We see that CDI is been bumped to version 2.0, mainly focusing on asynchronous events, and the Servlet API has been bumped to version 4.0, adding HTTP2 support. JSF 2.3, which is an API to build server-side UIs, the old JSF bean-managed model, has been removed and it's fully integrated with CDI. On the right-hand side of the figure in the previous section, you see the Bean Validation API, which has been bumped to version 2.0. It's tightly integrated with CDI and has been revamped to fully support Java 8 features such as streams and lambdas. There's also a totally new Security API for cloud security and past security in adding standardized authorization, authentication mechanisms, and APIs. Here, we want to focus on JAX-RS 2.1, JSON-P 1.1, and JSON-B 1.0.
Let's get started with JAX-RS 2.1. First, it improved the integration with CDI, so all your resource beans are properly CDI-managed. It's also been tightly integrated with JSON-B for JSON marshalling and JSON-P for JSON Processing. Also, server-sent events have been added to implement push notifications. They support non-blocking I/O and all the providers, such as filters and interceptors for JAX-RS. There's also been an improved JAX-RS, which is a synchronous client API supporting a completion stage. If you have a look at the Java API for JSON Processing, it's been updated to version 1.1 to support JSON Pointer and JSON Patch. It allows you to edit and transform operations for your JSON object model, and the API has been updated to work with Java SE 8 features, such as lambdas and streams.
The new kid on the block is JSON-B, the JSON Binding 1.0 API. It's the new standard way to convert JSON into Java objects and vice-versa. For a long time, we've had JSON-B to do the same for XML, and JSON-B is the API to do that for JSON. JSON-B leverages JSON-P and provides a conversion layer above it. It provides a default mapping algorithm for converting existing Java classes to JSON. The mapping is highly customizable through the use of Java annotations, and you can plug in different JSON-B runtimes to convert Java objects to and from JSON, such as Jackson. Those are the most relevant Java EE 8 APIs with respect to web-service development. In the next section, we're getting started with Java EE 8 microservices development.
