Rails / Ace Editor integration

application.js

//= require jquery
//= require jquery_ujs
//= require turbolinks
//= require_tree .
//= require ace/ace
//= require ace/theme-twilight
//= require ace/mode-java
//= require jquery-ace.min

Gemfile

gem 'jquery-ace-rails'

index.html.erb

<textarea id="editor" rows="30" style="width: 100%">
public class Test {

  public static void main(String[] args) throws Exception {
    System.out.println("Hello world!");
  }

}
</textarea>

<script>
  $('#editor').ace({ theme: 'twilight', lang: 'java' })
</script>

How to enable code autocomplete and warning message?

Also theme-textmate is not loading properly

ace.self-65bf62b01961ec59268304e974a57d9c575367012b6427c0698087a33c0102c8.js?body=1:1 GET http://localhost:3000/admin/affiliate_partners/theme-textmate.js 404 (Not Found)