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.

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

@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
}

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;
    }
}

<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>

<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>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.2</version>
        </dependency>
    </dependencies>