title: Simple GWT RequestFactory crashes
body: <p>Used this <a href="http://code.google.com/webtoolkit/doc/latest/DevGuideRequestFactory.html" rel="nofollow">http://code.google.com/webtoolkit/doc/latest/DevGuideRequestFactory.html</a> tutorial to understand the basic concepts, but having problems running my app from Eclipse:</p>
  
  <pre><code>15:48:04.384 [ERROR] [Main] Uncaught exception escaped
  com.google.web.bindery.event.shared.UmbrellaException: One or more exceptions caught, see full set in UmbrellaException#getCauses
      at com.google.web.bindery.requestfactory.shared.impl.AbstractRequestContext.fail(AbstractRequestContext.java:727)
      at com.google.web.bindery.requestfactory.shared.impl.AbstractRequestContext$5.onTransportFailure(AbstractRequestContext.java:1104)
      at com.google.web.bindery.requestfactory.gwt.client.DefaultRequestTransport$1.onResponseReceived(DefaultRequestTransport.java:140)
      at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
      at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
      at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
      at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
      at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337)
      at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218)
      at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
      at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
      at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
      at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
      at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
      at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:213)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
      at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
      at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
      at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:292)
      at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:546)
      at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:363)
      at java.lang.Thread.run(Unknown Source)
  Caused by: java.lang.RuntimeException: Server Error 500 &lt;html&gt;
  &lt;head&gt;
  &lt;meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"/&gt;
  &lt;title&gt;Error 500 INTERNAL_SERVER_ERROR&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;&lt;h2&gt;HTTP ERROR: 500&lt;/h2&gt;&lt;pre&gt;INTERNAL_SERVER_ERROR&lt;/pre&gt;
  &lt;p&gt;RequestURI=/gwtRequest&lt;/p&gt;&lt;p&gt;&lt;i&gt;&lt;small&gt;&lt;a href="http://jetty.mortbay.org/"&gt;Powered by Jetty://&lt;/a&gt;&lt;/small&gt;&lt;/i&gt;&lt;/p&gt;&lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;br/&gt;                                                
  &lt;/body&gt;
  &lt;/html&gt;
      at com.google.web.bindery.requestfactory.shared.Receiver.onFailure(Receiver.java:44)
      at com.google.web.bindery.requestfactory.shared.impl.AbstractRequest.onFail(AbstractRequest.java:118)
      at com.google.web.bindery.requestfactory.shared.impl.AbstractRequestContext.fail(AbstractRequestContext.java:707)
      at com.google.web.bindery.requestfactory.shared.impl.AbstractRequestContext$5.onTransportFailure(AbstractRequestContext.java:1104)
      at com.google.web.bindery.requestfactory.gwt.client.DefaultRequestTransport$1.onResponseReceived(DefaultRequestTransport.java:140)
      at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
      at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
      at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
      at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
      at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337)
      at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218)
      at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
      at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
      at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
      at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
      at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
      at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:213)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
      at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
      at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
      at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:292)
      at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:546)
      at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:363)
      at java.lang.Thread.run(Unknown Source)
  </code></pre>
  
  <p>Here's the code that fails:</p>
  
  <pre><code>final EventBus eventBus = new SimpleEventBus();
  final TestEntityRequestFactory requestFactory = GWT.create(TestEntityRequestFactory.class);
  requestFactory.initialize(eventBus);
  
  final Button button = new Button("omg");
  RootPanel.get().add(button);
  
  TestEntityRequest testEntityRequest = requestFactory.testEntityRequest();
  Request&lt;String&gt; createReq = testEntityRequest.getOmg();
  createReq.fire(new Receiver&lt;String&gt;() {
      @Override
      public void onSuccess(String arg0) {
          button.setText(arg0);           
      }
  });
  </code></pre>
  
  <p>I know my question is quite abstract, please use comments to ask for required details.</p>