SampleController.java

import javax.ejb.Stateless;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;

@Stateless
@Path("/sample")
public class SampleController {

    @GET
    @Produces("text/plain")
    public String sample() {
        return "Hello World";
    }

    public static void main(String args[]) {
        TomEEApplication.run(HelloWorldServlet.class, SampleController.class);
    }
}

Do you need HelloWorldServlet.class referenced on line 17? Blog post does not explain it's purpose?