title: High CPU due to SpEL in Message Handlers
body: <p>We experience extremly high CPU (15 cores on 100%) when running high load on our application. The profiles shows that 20%+ is used by SpEL wich is used mostly by the ServiceActivatingHandler. The applicatin uses service activators to handle messages but never uses any SpEL. </p>
  
  <p>There's about 12 ServiceActivators in a flow which are defined as follows:</p>
  
  <p><code>&lt;service-activator ref="myService"/&gt;</code> 
  or 
  <code>&lt;service-activator ref="myService" method="addStuff"/&gt;</code></p>
  
  <p>Most signatures are as follows:</p>
  
  <p><code>@ServiceActivator
  public Message&lt;String&gt; handle(Message&lt;String&gt;, @Header("header1") String header1, @Header("header2") String header2, @Header("header3") String header3)</code></p>
  
  <p>Profiling screenshot:
  <a href="https://i.stack.imgur.com/WcUkF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WcUkF.png" alt="Profiling screenshot"></a></p>
  
  <p>How can this expression evaluation be avoided? Application runs on SprintBoot and SpringIntegration 4.3.x</p>