title: Are multiple requests handled by single thread in Spring Boot until certain requests threshold is reached?
body: <p>In my Spring Boot 2.1.6 project (based on Tomcat) I have a rest controller. I added a default constructor to it which prints something. I thought in Tomcat-based servers each request is handled in separate thread. So I expected each request to trigger a new controller object and as a result new print from the constructor. However, I made a test of sending 30 requests to the rest controller and I only see that the print was made once. So as far as I understand the rest controller handles all those requests in one thread. </p>
  
  <p>My question is whether indeed multiple requests are handled in a single thread or maybe there's certain request threshold upon which another thread will be opened? I'm using default Spring Boot configuration perhaps this is controlled somewhere in the config?</p>
  
  <p>This is the code for my controller:</p>
  
  <pre><code>@RestController
  public class TrackingEventController {
  
      public TrackingEventController() {
          System.out.println("from TrackingEventController");
      }
  
      @RequestMapping(method=GET, path=trackingEventPath)
      public ResponseEntity&lt;Object&gt; handleTrackingEvent(
              @RequestParam(name = Routes.event) String event,
              @RequestParam(name = Routes.pubId) String pubId,
              @RequestParam(name = Routes.advId) String advId) {
  
          return new ResponseEntity&lt;&gt;(null, new HttpHeaders(), HttpStatus.OK);
      }
  }
  </code></pre>