This project shows how we can support JSON with our JAX-RS web services, using Jackson.
The web service itself is identical in functionality to the Parolee service introduced in Example 05. However, this time, it's set up to exchange data between client and service using JSON as the data format.
JAX-RS does not natively support this format. However, as JSON is such a commonly-used data format, adding this support is incredibly easy. All we need to do is include one extra dependency in our POM file - on resteasy-jackson2-provider. We can see this dependency on line 48 of our POM. This dependency itself depends on the Jackson libraries (e.g. jackson-core, jackson-databind, jackson-annotations), so we don't need to manually add those dependencies ourselves - they'll be added automatically for us.
Now, whenever we mark one of end points as producing or consuming "application/json" (we can use the constant MediaType.APPLICATION_JSON to avoid hardcoding), Jackson will be used to serialize / deserialize outgoing / incoming HTTP responses / requests.
Unlike Example 07, there is no need to include a custom MessageBodyReader / MessageBodyWriter implementation - these are provided by the extra dependency we added. Furthermore, JAX-RS can detect that the dependency contains these implementations, and will automatically configure our application with them without us having to manually reference them.
Similarly, when creating a new Client instance, we also do not need to configure it with references to any custom readers / writers. Compare the implementation of ParoleeResourceIT's createClient() method, in this project and Example 07.