title: How to separate interface from implementation in Grails services?
body: <p>I was wondering if it's possible to create a service interface on Grails and I can't find a proper way of doing it.
  This explanation isn't satisfactory, since it seems to mix Java and Groovy:</p>
  
  <p><a href="http://www.grails.org/doc/latest/guide/8.%20The%20Service%20Layer.html" rel="noreferrer">http://www.grails.org/doc/latest/guide/8.%20The%20Service%20Layer.html</a></p>
  
  <p>It seems to me like a bad design flaw of the framework, given that the interface mechanism is one of the best features of Java (and most OO languages).</p>
  
  <p>Any idea to clarify this issue?</p>
  
  <p>Thanks!
  Mulone</p>