title: Scala style for empty class parameter lists
body: <p>When creating an object without class parameters, I am having difficulty deciding whether I should include empty parentheses or not. A specific example: I am interfacing with existing Java code, and creating an object that implements an interface called EventResponder. Should I write:</p>
  
  <pre><code>val service = new EventResponder() {
    def respond(message: String): String = {
      return ""
    }
  }
  </code></pre>
  
  <p>or</p>
  
  <pre><code>val service = new EventResponder {
    def respond(message: String): String = {
      return ""
    }
  }
  </code></pre>
  
  <p>(Or, BTW, is there something else I should change here?)</p>
  
  <p>Both seem to work, and as far as I can see, the Scala style guide does not have any recommendations for this. It talks about when to include empty parentheses for methods or arity-0, but that's not quite the same case.</p>