title: How to use TomcatEmbeddedServletContainerFactory with a AbstractAnnotationConfigDispatcherServletInitializer
body: <p>I have found 'TomcatEmbeddedServletContainerFactory' from the Spring Boot project which can create a Tomcat embedded instance.
  I already have a set of "traditional" Spring (Java based) configuration classes plus a 'AbstractAnnotationConfigDispatcherServletInitializer' implementation for setting up a root application context and the controller context</p>
  
  <pre><code>public class IntegrationTestDispatcherServletInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
  @Override
  protected String[] getServletMappings() {
      return new String[]{"/"};
  }
  
  @Override
  protected Class&lt;?&gt;[] getRootConfigClasses() {
      return new Class&lt;?&gt;[]{ServiceModuleConfiguration.class};
  }
  
  @Override
  protected Class&lt;?&gt;[] getServletConfigClasses() {
      return new Class&lt;?&gt;[]{WebModuleConfiguration.class };
  }
  }
  </code></pre>
  
  <p>Now I try to create a Tomcat instance with</p>
  
  <pre><code>TomcatEmbeddedServletContainerFactory tomcatFactory = new TomcatEmbeddedServletContainerFactory("/", 8080);
  tomcatFactory.getEmbeddedServletContainer(???)
  </code></pre>
  
  <p>getEmbeddedServletContainer() expects a  ServletContextInitializer from Spring boot and now I'm stuck with bridging that to my configuration classes.</p>
  
  <p><strong>Is Spring Boot's tomcat factory built for supporting this?</strong> If so,any examples out there?</p>