MessageBodyWriter not found for media type=application/json

Question

I am facing issues while consuming JAX-RS services as JSON.

Below I have added my code.

This is my service class:

//Sets the path to base URL + /hello
@Path("/hello") 
@Consumes(MediaType.APPLICATION_JSON)
@Produces(MediaType.APPLICATION_JSON)
public class Hello {

    @GET
    @Produces("application/json")
    public Student getStudent() {

        Student s = new Student();
        s.first_name = "Test First Name !!!";
        s.last_name = "Test Last Name!!!";

        return s;
    }

Student class which I am trying to get from service:

@XmlRootElement
public class Student implements Serializable {

    public String first_name;
    public String last_name;

    public String getFirst_name() {
        return first_name;
    }

    public void setFirst_name(String first_name) {
        this.first_name = first_name;
    }

    public String getLast_name() {
        return last_name;
    }

    public void setLast_name(String last_name) {
        this.last_name = last_name;
    }

    public Student()
    {
        first_name = "Fahad";
        last_name = "Mullaji";
    }
}

Web XML on service side.

<?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>com.vogella.jersey.first</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>com.vogella.jersey.first</param-value>
        </init-param>
        <init-param>
            <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
            <param-value>true</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> 

I don't know how to fix this issue. I am using SOAP UI for testing JSON response but I guess that it should not matter.

Many places I read that I need to add the code below. But I don't know where. I am not using Maven for building.

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-moxy</artifactId>
</dependency>

Server is looking for function to parse Student object to JSON but it is not able to find function or jar file for it. I have added jar of Genson, Moxy, RESTEasy and Jackson but I think that's the problem. I think I am missing mapping somewhere.

Answer 1

You've to create empty constructor because JAX-RS initializes the classes... Your constructor must have no arguments:

@XmlRootElement
public class Student implements Serializable {

    public String first_name;
    public String last_name;

    public String getFirst_name() {
        return first_name;
    }

    public void setFirst_name(String first_name) {
        this.first_name = first_name;
    }

    public String getLast_name() {
        return last_name;
    }

    public void setLast_name(String last_name) {
        this.last_name = last_name;
    }

    public Student()
    {
        first_name = "Fahad";
        last_name = "Mullaji";
    }


 public Student()
    {
    }
}

Answer 2

I was able to fix it by install jersey-media-json-jackson

Add the dependency to pom.xml

<dependency>
  <groupId>org.glassfish.jersey.media</groupId>
  <artifactId>jersey-media-json-jackson</artifactId>
  <scope>runtime</scope>
</dependency>

Answer 3

I was in the same situation where
- I was not using Maven or Ant,
- I finished this Vogella tutorial on Jersey,
- and I was getting the MessageBodyWriter error when trying to use @Produces(MediaType.APPLICATION_JSON).

This answer by @peeskillet solves the problem - you have to use the Jackson *.jar files that are available from the FasterXML Jackson Download page. You'll need the core files as well as the jaxrs files.

I added them to my WebContent/WEB-INF/lib folder where I have my Jersey *.jar files per the above tutorial, and made the small change to the web.xml file below (again, as originally shared by @peeskillet):

<param-name>jersey.config.server.provider.packages</param-name>
<param-value>
    your.other.package.here, com.fasterxml.jackson.jaxrs.json 
</param-value>

The important part being com.fasterxml.jackson.jaxrs.json.

Answer 4

Uncommenting the below code helped

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-moxy</artifactId>
</dependency>

which was present in pom.xml in my maven based project resolved this error for me.

Answer 5

Below should be in your pom.xml above other jersy/jackson dependencies. In my case it as below jersy-client dep-cy and i got MessageBodyWriter not found for media type=application/json.

<dependency>
  <groupId>org.glassfish.jersey.media</groupId>
  <artifactId>jersey-media-json-jackson</artifactId>
  <version>2.25</version>
</dependency>