title: GWT - failure on async method call
body: <p>What is the reason why the onFailure(...) method is called when I do a async method call? The console output says always "ERROR!!!!".</p>
  
  <p>MyEntryPoint.java:</p>
  
  <pre><code>package com.example.smartgwtproject.client;
  
  import com.google.gwt.core.client.EntryPoint;
  import com.google.gwt.core.client.GWT;
  import com.google.gwt.user.client.rpc.AsyncCallback;
  //...
  
  public class MyEntryPoint implements EntryPoint {
      public void onModuleLoad() {
          GreetingServiceAsync service = (GreetingServiceAsync) GWT.create(GreetingService.class);
          //...
  
          service.getFileList(new AsyncCallback&lt;List&lt;String&gt;&gt;(){
  
              @Override
              public void onFailure(Throwable caught) {
                  System.out.println("ERROR!!!!");
              }
  
              @Override
              public void onSuccess(List&lt;String&gt; result) {
                  System.out.println("OK!");
              }
          });
          //...
      }
  }
  </code></pre>
  
  <p>.gwt.xml:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 2.5.1//EN"
    "http://google-web-toolkit.googlecode.com/svn/tags/2.5.1/distro-source/core/src/gwt-module.dtd"&gt;
  &lt;module rename-to='dlaconfigcenter'&gt;
  
    &lt;inherits name='com.google.gwt.user.User'/&gt;
    &lt;inherits name="com.smartgwt.SmartGwt"/&gt;
  
    &lt;entry-point class='com.example.smartgwtproject.client.MyEntryPoint'/&gt;
  
    &lt;source path='client' /&gt;
    &lt;source path='shared' &gt;
      &lt;include name="GreetingServiceImpl.java"/&gt;
    &lt;/source&gt;
  
  &lt;/module&gt;
  </code></pre>
  
  <p>GreetingService:</p>
  
  <pre><code>package com.example.smartgwtproject.client;
  
  //...
  
  @RemoteServiceRelativePath("greet")
  public interface GreetingService extends RemoteService {
      List&lt;String&gt; getFileList();
  }
  </code></pre>
  
  <p>GreetingServiceAsync:</p>
  
  <pre><code>//...
  
  public interface GreetingServiceAsync {
  
      void getFileList(AsyncCallback&lt;List&lt;String&gt;&gt; callback);
  }
  </code></pre>