code: protected String getSerializerClass(String resource, String urlLastElement) {
  		String serializerClass = null;
  		String extension = this.utils.getExtension(urlLastElement);
  		if (extension != null) {
  			SerializerFinder finder = new SerializerFinder(config, extension);
  			serializerClass = finder.findResource(resource);
  		}
  		return serializerClass;
  	}
docs: Gets serializer class for a resource. If the last part of the URL has an
  extension, then could be a Serializer class to render the result in a
  specific way. If the extension is .xml it hopes that a
  ResourceNameXmlSerializer exists to render the resource as Xml. The
  extension can be anything.
  
  @param resource
  Resource that will managed by the controller class.
  @param urlLastElement
  Last element of the URL analyzed.
  @return The fully qualified name of the serializer class for this
  resource and extension.