Problem with Restful WebService

Question

I am working on RestFul Webservice, I wrote a small reassured service that returns json data, here is my code:

@Path("/test")

public class TestService {

@GET
@Produces(MediaType.APPLICATION_JSON)
public String sayHello() {
    return "<h6> Hello, Welcome to the world of REST (Plain Text) </h6>";
}
@GET
@Path("dbdetails")
@Produces(MediaType.APPLICATION_JSON)
public Map<String, List> getDBDetails() {
    System.out.println("ramesh kumar ");
    List<ProductCategories> list = new ArrayList<ProductCategories>();
    HashMap<String,List> map = new HashMap<String,List>();
    ProductCategories cat = new ProductCategories();
    cat.setId(1);
    cat.setImage("Image21");
    cat.setName("Electronics");
    cat.setRowid(111);
    cat.setType("CatType");
    list.add(cat);
    map.put("Ramesh",list);
    System.out.println("ramesh kumar ");
    return map;

}

But I get an error message:

SEVERE: message body writer for type Java, class java.util.HashMap, and media type MIME, application / json, not found March 3, 2011 3:32:41 PM com.sun.jersey.server.impl.application.WebApplicationImpl onException SEVERE: internal javax.ws.rs.WebApplicationException server error

Any ideas?

Answer 1

JAXB . -, jersey-json, JSON. . -, JAXB , , . JAXB, @XmlRootElement. , , , , . 100% GenericEntity, , , . , :

• JAXBElement.
• , @XmlRootElement.

, . jersey users list list archive.

Answer 2

. GenericEntity . :

public GenericEntity<Map<String, List>> getDBDetails() { 
.
.
.
        return  new GenericEntity<Map<String, List>> (map) {};
}