put model into play (1.x framework) session

Application.java

package controllers;

import play.*;
import play.mvc.*;
import java.util.*;
import models.*;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.DeserializationConfig;
import java.io.IOException;

public class Application extends Controller {

  // The Play! session is not living on the server side but on the client side.
  // In fact, it is stored in a signed cookie. This session is therefore limited to 4kb.
  //
  // It is NOT recommended to store a model in a play session as it may contain a huge object graph
  //
  public static ObjectMapper mapper = new ObjectMapper();

  public static void index() throws JsonGenerationException, JsonMappingException, IOException {
    User user1 = new User("bob", 37);
    mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    session.put("user", mapper.writeValueAsString(foo1));

    User user2 = mapper.readValue(session.get("user"), User.class);
    Logger.info("name: %s, age: %s", user2.name, user2.age);

    render();
  }
}

dependency.yml

require:
    - play
    - org.codehaus.jackson -> jackson-mapper-asl 1.9.13