title: Grails: Services VS Groovy classes
body: <p>Documentation says: </p>
  
  <blockquote>
    <p>The Grails team discourages the
    embedding of core application logic
    inside controllers, as it does not
    promote re-use and a clean separation
    of concerns.</p>
  </blockquote>
  
  <p>I have one API controller and a few Groovy classes in src/groovy folder. Those classes just implements my application logic so actions in API controller works in this way:</p>
  
  <pre><code>//index page
  def index = {
      render new IndexApi().index(params) as JSON
  }
  </code></pre>
  
  <p>I'm curious - is there any reason to move my application logic from plain groovy classes into services ?</p>