title: IllegalArgumentException occured : id to load is required for loading?
body: <p>When I try to access the findById it is showing the following:</p>
  
  <pre><code>IllegalArgumentException "id to load is required for loading"
  </code></pre>
  
  <p>Here's my code:</p>
  
  <pre><code>package controllers;
  import play.*;
  import play.mvc.*;
  import java.util.*;
  import models.*;
  
  public class Application extends Controller {
  
      public static void index() {
  
         render();
      }
      public static void saveUser(String name)
      {
          User1 user =new User1(name);
          String res = "";
          if( user.save()!=null){
              res="Stored Successfully";
          }
          else{
              res="Failed to store";
          }
          render(res);
      }
      public static void showUser(Long id)
      {
         User1 user=  User1.findById(id);
         render(user);
      }
  
  }
  </code></pre>
  
  <p>and below is my routes file i don't understand why the error is coming and illegal argument exception.
      # Routes
      # This file defines all application routes (Higher priority routes first)
      # ~~~~</p>
  
  <pre><code># Home page
  GET     /                                       Application.index
  
  # Ignore favicon requests
  GET     /favicon.ico                            404
  
  # Map static resources from the /app/public folder to the /public path
  GET     /public/                                staticDir:public
  
  # Catch all
  *       /{controller}/{action}                  {controller}.{action}
  </code></pre>