title: Grails: difference between a plain class and a command object?
body: <p>In Grails, one can define a Command object class by calling it <em>ClassName</em>Command and use it as a container to pass data around. But what are the difference between that and a plain class defined in <code>/src/</code>?</p>
  
  <p>This question stems from <a href="https://stackoverflow.com/questions/28908364/grails-is-it-possible-to-prevent-a-domain-class-instance-from-being-persisted">Grails: Is it possible to prevent a domain class instance from being persisted?</a> when someone suggested to create a Command object, but it would appear that a plain class inheriting from a Domain class would work just as well...</p>