package com.mycompany.maptojson.rest;

import java.util.HashMap;
import java.util.Map;
import javax.ws.rs.Path;
import javax.ws.rs.GET;
import javax.ws.rs.Produces;
import javax.enterprise.context.RequestScoped;

@Path("maps")
@RequestScoped
public class MapToJson {

    @GET
    @Produces("application/json")
    public Map getJson() {
       Map<String, String> theMap = new HashMap<>();
       theMap.put("foo", "bar");
       return theMap;
    }
}

package com.mycompany.maptojson.rest;

import java.util.Set;
import javax.ws.rs.core.Application;

@javax.ws.rs.ApplicationPath("webresources")
public class ApplicationConfig extends Application {

    @Override
    public Set<Class<?>> getClasses() {
        Set<Class<?>> resources = new java.util.HashSet<>();
        // following code can be used to customize Jersey 2.0 JSON provider:
        try {
            Class jsonProvider = Class.forName("org.glassfish.jersey.jackson.JacksonFeature");
            // Class jsonProvider = Class.forName("org.glassfish.jersey.moxy.json.MoxyJsonFeature");
            // Class jsonProvider = Class.forName("org.glassfish.jersey.jettison.JettisonFeature");
            resources.add(jsonProvider);
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(getClass().getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        addRestResourceClasses(resources);
        return resources;
    }

    private void addRestResourceClasses(Set<Class<?>> resources) {
        resources.add(com.mycompany.maptojson.rest.MapToJson.class);
    }
}

Class.forName("org.glassfish.jersey.jackson.JacksonFeature");

Class.forName("org.glassfish.jersey.moxy.json.MoxyJsonFeature");

Class.forName("org.glassfish.jersey.jettison.JettisonFeature");

@Path("myResource")
public class MyResource {
  @GET
  @Produces(MediaType.APPLICATION_JSON)
  public Map<String, String> getMap() {
      Map<String, String> map = new HashMap<String, String>();
      map.put("some key", "some value");
      return map;
  }
}

// ... (client initialization)
Map<String, String> map = client.target().path("myResource").request("application/json").get(Map.class);

public class MyApp extends ResourceConfig {
  public MyApp() {
    super(MyResource.class, JacksonFeature.class);
  }
}

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

@GET
@Produces(MediaType.APPLICATION_JSON)
public Response getJson() {
    Map<String, String> testMap = new HashMap<>();
    testMap.put("Key1", "value1");
    testMap.put("key2", "value2");
    JSONObject obj = new JSONObject(testMap);

    return Response.status(200).entity(obj).build();
}

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-json-jackson</artifactId>
    <version>{latest version}</version>
</dependency>

public class BeanClass{
    private int duration, Id;
    private String description;
    private User user = new User();
    Map<String, String> map = new HashMap<>();
 }


@GET
@Produces({ MediaType.APPLICATION_JSON }) // , MediaType.APPLICATION_XML
public Response getAll() {
        List<BeanClass> lstBean = ...
        return Response.ok().entity(lstBean).build();
}