Configuração JSON-B

[
   {
      "Id":1,
      "Name":"user 1",
      "Registration":"2018-12-28"
   },
   {
      "Id":2,
      "Name":"user 2",
      "Registration":"2018-12-28"
   }
]

import jakarta.ws.rs.ApplicationPath;
import jakarta.ws.rs.core.Application;

@ApplicationPath("api")
public class JAXRSApplication extends Application {

}

import java.util.ArrayList;
import java.util.List;

import jakarta.ejb.Stateless;
import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

import org.superbiz.model.User;

@Path("users")
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
@Stateless
public class UserService {

    @GET
    public List<User> users() {
        List<User> users = new ArrayList<>();
        User user1 = new User(1, "user 1");
        User user2 = new User(2, "user 2");
        users.add(user1);
        users.add(user2);

        return users;
    }
}

import jakarta.json.bind.Jsonb;
import jakarta.json.bind.JsonbBuilder;
import jakarta.json.bind.JsonbConfig;
import jakarta.json.bind.config.PropertyNamingStrategy;
import jakarta.ws.rs.ext.ContextResolver;
import jakarta.ws.rs.ext.Provider;

@Provider
public class JSONBConfiguration implements ContextResolver<Jsonb> {

    private Jsonb jsonb;

    public JSONBConfiguration() {
        // jsonbConfig oferece muitas configurações.
        JsonbConfig config = new JsonbConfig().withFormatting(true)
                .withPropertyNamingStrategy(PropertyNamingStrategy.UPPER_CAMEL_CASE)
                .withDateFormat("yyyy - MM - dd", Locale.ENGLISH);

        jsonb = JsonbBuilder.create(config);
    }

    @Override
    public Jsonb getContext(Class<?> type) {
        return jsonb;
    }

}

package org.superbiz.rest;

import java.io.IOException;
import java.net.URL;
import java.time.LocalDate;
import java.time.Month;
import java.time.format.DateTimeFormatter;


import org.apache.cxf.jaxrs.client.WebClient;
import org.jboss.arquillian.container.test.api.Deployment;
import org.jboss.arquillian.junit.Arquillian;
import org.jboss.arquillian.test.api.ArquillianResource;
import org.jboss.shrinkwrap.api.ShrinkWrap;
import org.jboss.shrinkwrap.api.spec.WebArchive;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.superbiz.JAXRSApplication;
import org.superbiz.JSONBConfiguration;
import org.superbiz.model.User;

@RunWith(Arquillian.class)
public class UserServiceTest {

	@ArquillianResource
	private URL base;

	@Deployment(testable = false)
	public static WebArchive app() {
		return ShrinkWrap.create(WebArchive.class)
				.addClasses(UserService.class, JAXRSApplication.class, JSONBConfiguration.class, User.class);
	}

	@Test
	public void get() throws IOException {
		final String message = WebClient.create(base.toExternalForm()).path("api/users").get(String.class);
		System.out.println(message);


		String assertDate = LocalDate.of(2019, Month.JANUARY, 1)
				.format(DateTimeFormatter.ofPattern("yyyy - MM - dd"));

		System.out.println(assertDate);
		// test withDateFormat("yyyy - MM - dd")
		Assert.assertTrue(message.contains(assertDate));
		// test withFormatting(true)
		Assert.assertTrue(message.contains("\n"));
	}

}

Running org.superbiz.rest.UserServiceTest
INFO: Starting TomEE from: /tmp/arquillian-apache-tomee-23754
INFO: Starting Servlet engine: [Apache Tomcat/11.0.25]
INFO: Starting ProtocolHandler ["http-nio-52978"]
INFO: Configuring enterprise application: /path/to/tomee/examples/jsonb-configuration/target/tomee-embedded/0/3e85ced9-0908-4b9e-8993-d5f11b448e1a
INFO: Enterprise application "/path/to/tomee/examples/jsonb-configuration/target/tomee-embedded/0/3e85ced9-0908-4b9e-8993-d5f11b448e1a" loaded.
INFO: Deployed Application(path=/path/to/tomee/examples/jsonb-configuration/target/tomee-embedded/0/3e85ced9-0908-4b9e-8993-d5f11b448e1a)
INFO: Provider{clazz=org.superbiz.JSONBConfiguration, discovered=true, singleton=false}
INFO: REST Application: http://localhost:52978/3e85ced9-0908-4b9e-8993-d5f11b448e1a/api       -> org.superbiz.JAXRSApplication
INFO:      Service URI: http://localhost:52978/3e85ced9-0908-4b9e-8993-d5f11b448e1a/api/users ->  EJB org.superbiz.rest.UserService
INFO:               GET http://localhost:52978/3e85ced9-0908-4b9e-8993-d5f11b448e1a/api/users ->      List<User> users()
[
  {
    "Id":1,
    "Name":"user 1",
    "Registration":"2019 - 01 - 01"
  },
  {
    "Id":2,
    "Name":"user 2",
    "Registration":"2019 - 01 - 01"
  }
]
2019 - 01 - 01
INFO: Undeploying app: /path/to/tomee/examples/jsonb-configuration/target/tomee-embedded/0/3e85ced9-0908-4b9e-8993-d5f11b448e1a
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 1.816 s -- in org.superbiz.rest.UserServiceTest
Results:

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0