Jersey 2.17: How to avoid MessageBodyWriter error in Jersey Server?

Question

I'm trying to write a simple Jersey server application. My code works fine only when I use XML. But when I request a result in JSON I get this error:

org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.aroundWriteTo MessageBodyWriter not found for media type={application/json, q=1000}, type=class il.zukermandl.jersey.demo.model.User, genericType=class il.zukermandl.jersey.demo.model.User.

Here is my simple Java code.

@Path("/users")
public class UserService {
    @GET
    @Produces({APPLICATION_JSON, APPLICATION_XML})
    public Response getUser() {        
        return ok(new User()).build();
    }
}

I use JAXB annotations for my entity.

@XmlRootElement(name = "user")
@XmlType(propOrder = {"id", "name", "age"})
public class User {
    private Long id;
    private String name;
    private Integer age;
    // getters,setters and ctrs were omitted
}

My config class.

public class AppConfig extends Application {
    @Override
    public Set<Class<?>> getClasses() {
        final Set<Class<?>> resources = new HashSet<Class<?>>();
        resources.add(il.zukermandl.jersey.demo.service.UserService.class);
        return resources;
    }
}

And web.xml descriptor.

    <servlet>
        <servlet-name>Application</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
            <param-name>jersey.config.server.provider.packages</param-name>
            <param-value>il.zukermandl.jersey.demo</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Application</servlet-name>
        <url-pattern>/rest_v1/*</url-pattern>
    </servlet-mapping>

I think the main issue is in my pom.xml file. So here it is

    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-servlet</artifactId>
            <version>2.17</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.media</groupId>
            <artifactId>jersey-media-json-jackson</artifactId>
            <version>2.17</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.3.2</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.3.2</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.3.2</version>
        </dependency>            
    </dependencies>

I use Tomcat 8.0.9 to run my code. Any ideas how to add JSON support to this app?

UPD

Here is the structure of my project.

WEB-INF
    ├── classes
    │   ├── il
    │   │   └── zukermandl
    │   │       └── jersey
    │   │           └── demo
    │   │               ├── AppConfig.class
    │   │               ├── model
    │   │               │   └── User.class
    │   │               └── service
    │   │                   └── UserService.class
    │   └── misc.txt
    ├── lib
    │   ├── aopalliance-repackaged-2.4.0-b10.jar
    │   ├── hk2-api-2.4.0-b10.jar
    │   ├── hk2-locator-2.4.0-b10.jar
    │   ├── hk2-utils-2.4.0-b10.jar
    │   ├── javassist-3.18.1-GA.jar
    │   ├── javax.annotation-api-1.2.jar
    │   ├── javax.inject-2.4.0-b10.jar
    │   ├── javax.ws.rs-api-2.0.1.jar
    │   ├── jersey-client-2.17.jar
    │   ├── jersey-common-2.17.jar
    │   ├── jersey-container-servlet-2.17.jar
    │   ├── jersey-container-servlet-core-2.17.jar
    │   ├── jersey-guava-2.17.jar
    │   ├── jersey-media-jaxb-2.17.jar
    │   ├── jersey-server-2.17.jar
    │   ├── osgi-resource-locator-1.0.1.jar
    │   └── validation-api-1.1.0.Final.jar
    └── web.xml

Answer 1

Just in case someone else runs into same problem, I solved it by adding

shadowJar {
    mergeServiceFiles()
}

to build.gradle. Looks like plugin id "com.github.johnrengelman.shadow" version "4.0.3" does shadowing wrong way without it.