title: How to inject mock dependencies into GWT rpc service implementation using GWTTestCase
body: <p>I want to unit-test my gwt-rpc interaction against my real rpc endpoint <code>HelloServiceImpl</code>. This service implementation has some dependencies to do its work. I use the junit GWTTestCase, and a test-scope module gwt.xml specification:</p>
  
  <pre><code>&lt;module&gt;
      &lt;inherits name='...' /&gt;
      &lt;servlet path="/HelloService/helloService.rpc" class="my.package.HelloServiceImpl" /&gt;
  &lt;/module&gt;
  </code></pre>
  
  <p>It is unclear to me how to control the instantiation of the service. I see that GWTTestCase indirectly invokes the default constructor of <code>HelloServiceImpl</code>. The question is: how do I inject the mock dependencies during or after instatiotion of the <code>HelloServiceImpl</code>?</p>