title: Spring integration ServiceActivator autostartup flag
body: <p>I have a Spring Boot app with ServiceActivator annotated method for reading Message objects from a queue. Something like: </p>
  
  <pre class="lang-java prettyprint-override"><code>@EnableBinding(Sink.class)
  public class MyProcessor {
      @ServiceActivator(inputChannel = Sink.INPUT)
      public void process(final Message&lt;?&gt; message) {
         // ...
      }
  }
  </code></pre>
  
  <p>However, now I have a requirement to load a user script and use it to preprocess the messages' payloads. This load may fail or the script might not compile. If this happens, I want to not start up my sink and just leave the messages sitting on the queue until the problem is fixed and the app restarted.</p>
  
  <p>ServiceActivator has an autostartup attribute, so it seems like I could set that to false, and then start the sink manually when I'm satisfied that the script is OK. However, I can't figure out how or when to do that manual start.</p>