title: Spring Boot Application: No converter found for return value of type
body: <p>I am writing a simple <code>REST API</code> according to <a href="https://spring.io/guides/gs/actuator-service/" rel="noreferrer">this</a> Spring-Boot tutorial. On my local dev machines (<code>Ubuntu 15.04</code> and <code>Windows 8.1</code>) everything works like a charm.</p>
  
  <p>I have an old <code>32-bit</code> <code>Ubuntu 12.04 LTS</code> server lying around on which I wanted to deploy my <code>REST</code> service.</p>
  
  <p>The starting log is ok, but as soon as I send a <code>GET</code> request to the <code>/user/{id}</code> endpoint, I get the following error:</p>
  
  <pre><code>java.lang.IllegalArgumentException: No converter found for return value of type: class ch.gmazlami.gifty.models.user.User
  </code></pre>
  
  <p>And then down the stacktrace:</p>
  
  <pre><code>java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.LinkedHashMap
  </code></pre>
  
  <p>The entire stacktrace is posted <a href="http://pastebin.ca/3263361" rel="noreferrer">here</a>.</p>
  
  <p>I looked into some answers referring this error, but those don't seem to apply to my problem, since I'm using Spring-Boot, no <code>xml</code> configs whatsoever.</p>
  
  <p>The affected controller is:</p>
  
  <pre><code>    @RequestMapping(value = "/user/{id}", method = RequestMethod.GET)
  public ResponseEntity&lt;User&gt; getUser(@PathVariable Long id){
      try{
          return new ResponseEntity&lt;User&gt;(userService.getUserById(id), HttpStatus.OK);
      }catch(NoSuchUserException e){
          return new ResponseEntity&lt;&gt;(HttpStatus.NOT_FOUND);
      }
  }
  </code></pre>
  
  <p>Any help would be greatly appreciated. It is very weird since the exact same things work on other machines perfectly.</p>