title: Why is a synchronized block used in this example of IntentService?
body: <p>The Android documentation says the following about IntentService:</p>
  
  <blockquote>
    <p>[IntentService] creates a work queue that passes one intent at a time to your onHandleIntent() implementation, so you never have to worry about multi-threading.</p>
  </blockquote>
  
  <p>But in the example that follows, they use a synchronized block in method onHandleIntent as if it is expected to be executed simultaneously.</p>
  
  <pre><code>protected void onHandleIntent(Intent intent) {
      synchronized (this) {
          Some operations...
      }
  }
  </code></pre>
  
  <p>Why are they using synchronized here? Am I missing something?</p>