Jersey returns 500 when trying to return an XML response

Question

I'm trying to create my own RESTful WS application using Jersey 2.12 based from this article. I want to return an XML representation of a class depending on the id been passed from the url, however, I'm getting a 500 response code when trying from either Advanced Rest Client Application (google chrome app) or browser. Below are the details:

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns="http://java.sun.com/xml/ns/javaee" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-
    app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>WS_RESTful_Practice</display-name>
  <servlet>
    <servlet-name>Jersey REST Service</servlet-name>
    <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
    <!-- Register resources and providers under com.vogella.jersey.first package. -->
    <init-param>
        <param-name>jersey.config.server.provider.packages</param-name>
        <param-value>test.services</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
 </servlet>
 <servlet-mapping>
    <servlet-name>Jersey REST Service</servlet-name>
    <url-pattern>/rest/*</url-pattern>
 </servlet-mapping>
</web-app>

TestRestModel.java

package test.model;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class TestRestModel{

    /**
     * 
     */
    private static final long serialVersionUID = -8391589100962515747L;
    private String name;
    private String content;

    public TestRestModel(String name, String content){
        this.name = name;
        this.content = content;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }
}

TestResource.java

package test.services;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import test.dao.TestModelDao;
import test.model.TestRestModel;

@Path("/test")
public class TestResource {

    @GET
    @Path("{id}")
    public Response getModel(@PathParam("id") String id){
        return Response.ok().entity(TestModelDao.instance.getModel().get(id)).build();
    }
}

TestModelDao.java

package test.dao;

import java.util.HashMap;
import java.util.Map;
import test.model.TestRestModel;

public enum TestModelDao {
    instance;

    private Map<String, TestRestModel> container = new HashMap<String, TestRestModel>();

    private TestModelDao(){

        TestRestModel model = new TestRestModel("a", "this is first");
        container.put("1", model);
        model = new TestRestModel("b", "this is second");
        container.put("2", model);
        model = new TestRestModel("c", "this is third");
        container.put("3", model);
    }

    public Map<String, TestRestModel> getModel(){
        return container;
    }
}

I'm totally new to Jersey and REST. And I don't know how to log error from Jersey yet.

@zyexal thanks for the feedback. i don't know where to get the stacktrace and the web server doesn't print it neither. — anonymouse
If you start your server from your IDE (for example Eclipse) in debug mode, you should see something in you console view. Also you should be able to go through the code step by step then. So, try to enable debugging and report back afterwards ... — zyexal
@zyexal thanks. but that's the problem, the stacktrace doesnt print in the console. it just shows the server is started. — anonymouse

ACV ACV · Accepted Answer · 2015-10-20T20:47:43

This happens when you don't provide a default no arg constructor to your JAXB bean. So in your case you should amend the class by adding one:

  public TestRestModel(){

    }

This is due to a requirement in the JSR-222:

existing types, authored by users, are required to provide a no arg constructor. The no arg constructor is used by an unmarshaller during unmarshalling to create an instance of the type.

Jersey returns 500 when trying to return an XML response

4 Answers